261571622520540 has 96 divisors (see below), whose sum is σ = 776220783577344. Its totient is φ = 65586884428800.

The previous prime is 261571622520521. The next prime is 261571622520587. The reversal of 261571622520540 is 45025226175162.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 261571622520540.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 120927394 + ... + 123071433.

It is an arithmetic number, because the mean of its divisors is an integer number (8085633162264).

Almost surely, 2^{261571622520540} is an apocalyptic number.

261571622520540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261571622520540 is an abundant number, since it is smaller than the sum of its proper divisors (514649161056804).

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

261571622520540 is a wasteful number, since it uses less digits than its factorization.

261571622520540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 243999907 (or 243999905 counting only the distinct ones).

The product of its (nonzero) digits is 2016000, while the sum is 48.

The spelling of 261571622520540 in words is "two hundred sixty-one trillion, five hundred seventy-one billion, six hundred twenty-two million, five hundred twenty thousand, five hundred forty".