261631505697 has 16 divisors (see below), whose sum is σ = 355427727360. Its totient is φ = 171142128000.

The previous prime is 261631505689. The next prime is 261631505701. The reversal of 261631505697 is 796505136162.

It is not a de Polignac number, because 261631505697 - 2³ = 261631505689 is a prime.

It is not an unprimeable number, because it can be changed into a prime (261631505677) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1672929 + ... + 1822622.

It is an arithmetic number, because the mean of its divisors is an integer number (22214232960).

Almost surely, 2^261631505697 is an apocalyptic number.

It is an amenable number.

261631505697 is a deficient number, since it is larger than the sum of its proper divisors (93796221663).

261631505697 is a wasteful number, since it uses less digits than its factorization.

261631505697 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3496024.

The product of its (nonzero) digits is 2041200, while the sum is 51.

The spelling of 261631505697 in words is "two hundred sixty-one billion, six hundred thirty-one million, five hundred five thousand, six hundred ninety-seven".