1231051999 has 2 divisors, whose sum is σ = 1231052000. Its totient is φ = 1231051998.

The previous prime is 1231051979. The next prime is 1231052027. The reversal of 1231051999 is 9991501321.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1231051999 - 2²³ = 1222663391 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1231051979) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 615525999 + 615526000.

It is an arithmetic number, because the mean of its divisors is an integer number (615526000).

Almost surely, 2^1231051999 is an apocalyptic number.

1231051999 is a deficient number, since it is larger than the sum of its proper divisors (1).

1231051999 is an equidigital number, since it uses as much as digits as its factorization.

1231051999 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 21870, while the sum is 40.

The square root of 1231051999 is about 35086.3506081781. The cubic root of 1231051999 is about 1071.7466447453.

The spelling of 1231051999 in words is "one billion, two hundred thirty-one million, fifty-one thousand, nine hundred ninety-nine".