261551107678331 has 2 divisors, whose sum is σ = 261551107678332. Its totient is φ = 261551107678330.

The previous prime is 261551107678283. The next prime is 261551107678361. The reversal of 261551107678331 is 133876701155162.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261551107678331 is a prime.

It is a super-2 number, since 2×261551107678331² (a number of 30 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (261551107678361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130775553839165 + 130775553839166.

It is an arithmetic number, because the mean of its divisors is an integer number (130775553839166).

Almost surely, 2^{261551107678331} is an apocalyptic number.

261551107678331 is a deficient number, since it is larger than the sum of its proper divisors (1).

261551107678331 is an equidigital number, since it uses as much as digits as its factorization.

261551107678331 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6350400, while the sum is 56.

The spelling of 261551107678331 in words is "two hundred sixty-one trillion, five hundred fifty-one billion, one hundred seven million, six hundred seventy-eight thousand, three hundred thirty-one".