261887976631 has 2 divisors, whose sum is σ = 261887976632. Its totient is φ = 261887976630.

The previous prime is 261887976613. The next prime is 261887976667. The reversal of 261887976631 is 136679788162.

Together with previous prime (261887976613) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261887976631 is a prime.

It is a super-2 number, since 2×261887976631² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261887976131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130943988315 + 130943988316.

It is an arithmetic number, because the mean of its divisors is an integer number (130943988316).

Almost surely, 2^261887976631 is an apocalyptic number.

261887976631 is a deficient number, since it is larger than the sum of its proper divisors (1).

261887976631 is an equidigital number, since it uses as much as digits as its factorization.

261887976631 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36578304, while the sum is 64.

The spelling of 261887976631 in words is "two hundred sixty-one billion, eight hundred eighty-seven million, nine hundred seventy-six thousand, six hundred thirty-one".