261978973272 has 40 divisors (see below), whose sum is σ = 733783700100. Its totient is φ = 87326324208.

The previous prime is 261978973253. The next prime is 261978973273. The reversal of 261978973272 is 272379879162.

261978973272 is a `hidden beast` number, since 2 + 619 + 7 + 8 + 9 + 7 + 3 + 2 + 7 + 2 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261978973273) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 202143622 + ... + 202144917.

Almost surely, 2^261978973272 is an apocalyptic number.

It is an amenable number.

261978973272 is an abundant number, since it is smaller than the sum of its proper divisors (471804726828).

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

261978973272 is a wasteful number, since it uses less digits than its factorization.

261978973272 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 404288557 (or 404288544 counting only the distinct ones).

The product of its digits is 32006016, while the sum is 63.

The spelling of 261978973272 in words is "two hundred sixty-one billion, nine hundred seventy-eight million, nine hundred seventy-three thousand, two hundred seventy-two".