261274274520 has 64 divisors (see below), whose sum is σ = 895797515520. Its totient is φ = 59719833984.

The previous prime is 261274274519. The next prime is 261274274543. The reversal of 261274274520 is 25472472162.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 155519562 + ... + 155521241.

It is an arithmetic number, because the mean of its divisors is an integer number (13996836180).

Almost surely, 2^261274274520 is an apocalyptic number.

261274274520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261274274520 is an abundant number, since it is smaller than the sum of its proper divisors (634523241000).

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

261274274520 is a wasteful number, since it uses less digits than its factorization.

261274274520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 311040824 (or 311040820 counting only the distinct ones).

The product of its (nonzero) digits is 376320, while the sum is 42.

The spelling of 261274274520 in words is "two hundred sixty-one billion, two hundred seventy-four million, two hundred seventy-four thousand, five hundred twenty".