1231645637 has 2 divisors, whose sum is σ = 1231645638. Its totient is φ = 1231645636.

The previous prime is 1231645601. The next prime is 1231645643. The reversal of 1231645637 is 7365461321.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1216544641 + 15100996 = 34879^2 + 3886^2 .

It is a cyclic number.

It is not a de Polignac number, because 1231645637 - 2¹⁸ = 1231383493 is a prime.

It is a super-2 number, since 2×1231645637² = 3033901950282271538, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1231645637.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1231645687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 615822818 + 615822819.

It is an arithmetic number, because the mean of its divisors is an integer number (615822819).

Almost surely, 2^1231645637 is an apocalyptic number.

It is an amenable number.

1231645637 is a deficient number, since it is larger than the sum of its proper divisors (1).

1231645637 is an equidigital number, since it uses as much as digits as its factorization.

1231645637 is an evil number, because the sum of its binary digits is even.

The product of its digits is 90720, while the sum is 38.

The square root of 1231645637 is about 35094.8092600601. The cubic root of 1231645637 is about 1071.9188896477.

The spelling of 1231645637 in words is "one billion, two hundred thirty-one million, six hundred forty-five thousand, six hundred thirty-seven".