261772357600520 has 64 divisors (see below), whose sum is σ = 637064404326000. Its totient is φ = 96232337261568.

The previous prime is 261772357600511. The next prime is 261772357600667. The reversal of 261772357600520 is 25006753277162.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 143200425023044 + 118571932577476 = 11966638^2 + 10889074^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1099025855 + ... + 1099264014.

Almost surely, 2^{261772357600520} is an apocalyptic number.

261772357600520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261772357600520 is an abundant number, since it is smaller than the sum of its proper divisors (375292046725480).

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

261772357600520 is a wasteful number, since it uses less digits than its factorization.

261772357600520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2198290122 (or 2198290118 counting only the distinct ones).

The product of its (nonzero) digits is 7408800, while the sum is 53.

The spelling of 261772357600520 in words is "two hundred sixty-one trillion, seven hundred seventy-two billion, three hundred fifty-seven million, six hundred thousand, five hundred twenty".