123999011531 has 2 divisors, whose sum is σ = 123999011532. Its totient is φ = 123999011530.

The previous prime is 123999011509. The next prime is 123999011537. The reversal of 123999011531 is 135110999321.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 123999011531 - 2²² = 123994817227 is a prime.

It is a super-2 number, since 2×123999011531² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (123999011537) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61999505765 + 61999505766.

It is an arithmetic number, because the mean of its divisors is an integer number (61999505766).

Almost surely, 2^123999011531 is an apocalyptic number.

123999011531 is a deficient number, since it is larger than the sum of its proper divisors (1).

123999011531 is an equidigital number, since it uses as much as digits as its factorization.

123999011531 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 65610, while the sum is 44.

It can be divided in two parts, 1239990 and 11531, that added together give a palindrome (1251521).

The spelling of 123999011531 in words is "one hundred twenty-three billion, nine hundred ninety-nine million, eleven thousand, five hundred thirty-one".