261636403211 has 2 divisors, whose sum is σ = 261636403212. Its totient is φ = 261636403210.

The previous prime is 261636403157. The next prime is 261636403219. The reversal of 261636403211 is 112304636162.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261636403211 - 2²² = 261632208907 is a prime.

It is a super-2 number, since 2×261636403211² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (261636403219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130818201605 + 130818201606.

It is an arithmetic number, because the mean of its divisors is an integer number (130818201606).

Almost surely, 2^261636403211 is an apocalyptic number.

261636403211 is a deficient number, since it is larger than the sum of its proper divisors (1).

261636403211 is an equidigital number, since it uses as much as digits as its factorization.

261636403211 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 31104, while the sum is 35.

The spelling of 261636403211 in words is "two hundred sixty-one billion, six hundred thirty-six million, four hundred three thousand, two hundred eleven".