261666522671274 has 24 divisors (see below), whose sum is σ = 647936151376800. Its totient is φ = 74761863620328.

The previous prime is 261666522671269. The next prime is 261666522671287. The reversal of 261666522671274 is 472176225666162.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1038359216824 + ... + 1038359217075.

It is an arithmetic number, because the mean of its divisors is an integer number (26997339640700).

Almost surely, 2^{261666522671274} is an apocalyptic number.

261666522671274 is an abundant number, since it is smaller than the sum of its proper divisors (386269628705526).

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

261666522671274 is a wasteful number, since it uses less digits than its factorization.

261666522671274 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2076718433914 (or 2076718433911 counting only the distinct ones).

The product of its digits is 121927680, while the sum is 63.

The spelling of 261666522671274 in words is "two hundred sixty-one trillion, six hundred sixty-six billion, five hundred twenty-two million, six hundred seventy-one thousand, two hundred seventy-four".