12640657 has 2 divisors, whose sum is σ = 12640658. Its totient is φ = 12640656.

The previous prime is 12640633. The next prime is 12640687. The reversal of 12640657 is 75604621.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11350161 + 1290496 = 3369^2 + 1136^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12640657 is a prime.

It is not a weakly prime, because it can be changed into another prime (12640687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6320328 + 6320329.

It is an arithmetic number, because the mean of its divisors is an integer number (6320329).

Almost surely, 2^12640657 is an apocalyptic number.

It is an amenable number.

12640657 is a deficient number, since it is larger than the sum of its proper divisors (1).

12640657 is an equidigital number, since it uses as much as digits as its factorization.

12640657 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10080, while the sum is 31.

The square root of 12640657 is about 3555.3701635695. The cubic root of 12640657 is about 232.9466927851.

The spelling of 12640657 in words is "twelve million, six hundred forty thousand, six hundred fifty-seven".