261971607511 has 2 divisors, whose sum is σ = 261971607512. Its totient is φ = 261971607510.

The previous prime is 261971607481. The next prime is 261971607559. The reversal of 261971607511 is 115706179162.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 261971607511 - 2²⁵ = 261938053079 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261971602511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130985803755 + 130985803756.

It is an arithmetic number, because the mean of its divisors is an integer number (130985803756).

Almost surely, 2^261971607511 is an apocalyptic number.

261971607511 is a deficient number, since it is larger than the sum of its proper divisors (1).

261971607511 is an equidigital number, since it uses as much as digits as its factorization.

261971607511 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 158760, while the sum is 46.

The spelling of 261971607511 in words is "two hundred sixty-one billion, nine hundred seventy-one million, six hundred seven thousand, five hundred eleven".