1261513543680 has 2496 divisors, whose sum is σ = 5481806174208. Its totient is φ = 275188285440.

The previous prime is 1261513543657. The next prime is 1261513543727. The reversal of 1261513543680 is 863453151621.

1261513543680 is a `hidden beast` number, since 1 + 2 + 6 + 1 + 5 + 135 + 436 + 80 = 666.

It is a tau number, because it is divible by the number of its divisors (2496).

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 pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 34094960622 + ... + 34094960658.

It is an arithmetic number, because the mean of its divisors is an integer number (2196236448).

Almost surely, 2^{1261513543680} is an apocalyptic number.

1261513543680 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 1261513543680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2740903087104).

1261513543680 is an abundant number, since it is smaller than the sum of its proper divisors (4220292630528).

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

1261513543680 is a wasteful number, since it uses less digits than its factorization.

1261513543680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 142 (or 108 counting only the distinct ones).

The product of its (nonzero) digits is 518400, while the sum is 45.

The spelling of 1261513543680 in words is "one trillion, two hundred sixty-one billion, five hundred thirteen million, five hundred forty-three thousand, six hundred eighty".