261532572500 has 30 divisors (see below), whose sum is σ = 571919435010. Its totient is φ = 104613028000.

The previous prime is 261532572461. The next prime is 261532572551. The reversal of 261532572500 is 5275235162.

It can be written as a sum of positive squares in 5 ways, for example, as 117750549904 + 143782022596 = 343148^2 + 379186^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 52304015 + ... + 52309014.

It is an arithmetic number, because the mean of its divisors is an integer number (19063981167).

Almost surely, 2^261532572500 is an apocalyptic number.

261532572500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261532572500 is an abundant number, since it is smaller than the sum of its proper divisors (310386862510).

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

261532572500 is a wasteful number, since it uses less digits than its factorization.

261532572500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104613053 (or 104613036 counting only the distinct ones).

The product of its (nonzero) digits is 126000, while the sum is 38.

The spelling of 261532572500 in words is "two hundred sixty-one billion, five hundred thirty-two million, five hundred seventy-two thousand, five hundred".