1231955657 has 2 divisors, whose sum is σ = 1231955658. Its totient is φ = 1231955656.

The previous prime is 1231955639. The next prime is 1231955689. The reversal of 1231955657 is 7565591321.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1100646976 + 131308681 = 33176^2 + 11459^2 .

It is a cyclic number.

It is not a de Polignac number, because 1231955657 - 2⁸ = 1231955401 is a prime.

It is not a weakly prime, because it can be changed into another prime (1231955617) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 615977828 + 615977829.

It is an arithmetic number, because the mean of its divisors is an integer number (615977829).

Almost surely, 2^1231955657 is an apocalyptic number.

It is an amenable number.

1231955657 is a deficient number, since it is larger than the sum of its proper divisors (1).

1231955657 is an equidigital number, since it uses as much as digits as its factorization.

1231955657 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 283500, while the sum is 44.

The square root of 1231955657 is about 35099.2258746543. The cubic root of 1231955657 is about 1072.0088203890.

It can be divided in two parts, 12319 and 55657, that added together give a palindrome (67976).

The spelling of 1231955657 in words is "one billion, two hundred thirty-one million, nine hundred fifty-five thousand, six hundred fifty-seven".