1261503774720 has 456 divisors, whose sum is σ = 4998275434464. Its totient is φ = 288324845568.

The previous prime is 1261503774673. The next prime is 1261503774737. The reversal of 1261503774720 is 274773051621.

1261503774720 is a `hidden beast` number, since 1 + 2 + 6 + 1 + 503 + 7 + 74 + 72 + 0 = 666.

It is a super-2 number, since 2×1261503774720² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 82567722 + ... + 82582998.

Almost surely, 2^{1261503774720} is an apocalyptic number.

1261503774720 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 1261503774720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2499137717232).

1261503774720 is an abundant number, since it is smaller than the sum of its proper divisors (3736771659744).

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

1261503774720 is an frugal number, since it uses more digits than its factorization.

1261503774720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15331 (or 15294 counting only the distinct ones).

The product of its (nonzero) digits is 493920, while the sum is 45.

The spelling of 1261503774720 in words is "one trillion, two hundred sixty-one billion, five hundred three million, seven hundred seventy-four thousand, seven hundred twenty".