261421053037172 has 48 divisors (see below), whose sum is σ = 523330071976320. Its totient is φ = 111933036438912.

The previous prime is 261421053037141. The next prime is 261421053037201. The reversal of 261421053037172 is 271730350124162.

It is a happy number.

It is a super-2 number, since 2×261421053037172² (a number of 30 digits) contains 22 as substring.

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, 1142195498 + ... + 1142424350.

It is an arithmetic number, because the mean of its divisors is an integer number (10902709832840).

Almost surely, 2^{261421053037172} is an apocalyptic number.

It is an amenable number.

261421053037172 is an abundant number, since it is smaller than the sum of its proper divisors (261909018939148).

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

261421053037172 is a wasteful number, since it uses less digits than its factorization.

261421053037172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 266760 (or 266758 counting only the distinct ones).

The product of its (nonzero) digits is 423360, while the sum is 44.

The spelling of 261421053037172 in words is "two hundred sixty-one trillion, four hundred twenty-one billion, fifty-three million, thirty-seven thousand, one hundred seventy-two".