645752137 has 2 divisors, whose sum is σ = 645752138. Its totient is φ = 645752136.

The previous prime is 645752111. The next prime is 645752197. The reversal of 645752137 is 731257546.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 466084921 + 179667216 = 21589^2 + 13404^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645752137 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 645752137.

It is not a weakly prime, because it can be changed into another prime (645752197) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322876068 + 322876069.

It is an arithmetic number, because the mean of its divisors is an integer number (322876069).

Almost surely, 2^645752137 is an apocalyptic number.

It is an amenable number.

645752137 is a deficient number, since it is larger than the sum of its proper divisors (1).

645752137 is an equidigital number, since it uses as much as digits as its factorization.

645752137 is an evil number, because the sum of its binary digits is even.

The product of its digits is 176400, while the sum is 40.

The square root of 645752137 is about 25411.6535668185. The cubic root of 645752137 is about 864.3479719949.

The spelling of 645752137 in words is "six hundred forty-five million, seven hundred fifty-two thousand, one hundred thirty-seven".