1261388842560 has 3360 divisors, whose sum is σ = 6211765283328. Its totient is φ = 239303393280.

The previous prime is 1261388842559. The next prime is 1261388842561. The reversal of 1261388842560 is 652488831621.

1261388842560 is a `hidden beast` number, since 1 + 2 + 6 + 1 + 38 + 8 + 8 + 42 + 560 = 666.

It is an interprime number because it is at equal distance from previous prime (1261388842559) and next prime (1261388842561).

It is a tau number, because it is divible by the number of its divisors (3360).

It is a super-2 number, since 2×1261388842560² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a junction number, because it is equal to n+sod(n) for n = 1261388842497 and 1261388842506.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1261388842561) by changing a digit.

It is a polite number, since it can be written in 479 ways as a sum of consecutive naturals, for example, 11162733064 + ... + 11162733176.

Almost surely, 2^{1261388842560} is an apocalyptic number.

1261388842560 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1261388842560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3105882641664).

1261388842560 is an abundant number, since it is smaller than the sum of its proper divisors (4950376440768).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1261388842560 is a wasteful number, since it uses less digits than its factorization.

1261388842560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 231 (or 205 counting only the distinct ones).

The product of its (nonzero) digits is 4423680, while the sum is 54.

It can be divided in two parts, 126138 and 8842560, that added together give a palindrome (8968698).

The spelling of 1261388842560 in words is "one trillion, two hundred sixty-one billion, three hundred eighty-eight million, eight hundred forty-two thousand, five hundred sixty".