261665651514631 has 64 divisors (see below), whose sum is σ = 333049565721600. Its totient is φ = 200078721063936.

The previous prime is 261665651514581. The next prime is 261665651514643. The reversal of 261665651514631 is 136415156566162.

It is not a de Polignac number, because 261665651514631 - 2⁹ = 261665651514119 is a prime.

It is a super-2 number, since 2×261665651514631² (a number of 30 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261665651514031) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 5922829300 + ... + 5922873478.

It is an arithmetic number, because the mean of its divisors is an integer number (5203899464400).

Almost surely, 2^{261665651514631} is an apocalyptic number.

261665651514631 is a deficient number, since it is larger than the sum of its proper divisors (71383914206969).

261665651514631 is a wasteful number, since it uses less digits than its factorization.

261665651514631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62648.

The product of its digits is 23328000, while the sum is 58.

The spelling of 261665651514631 in words is "two hundred sixty-one trillion, six hundred sixty-five billion, six hundred fifty-one million, five hundred fourteen thousand, six hundred thirty-one".