645528757 has 2 divisors, whose sum is σ = 645528758. Its totient is φ = 645528756.

The previous prime is 645528739. The next prime is 645528769. The reversal of 645528757 is 757825546.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 613107121 + 32421636 = 24761^2 + 5694^2 .

It is a cyclic number.

It is not a de Polignac number, because 645528757 - 2²³ = 637140149 is a prime.

It is a super-2 number, since 2×645528757² = 833414752227930098, 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 645528757.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645529757) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322764378 + 322764379.

It is an arithmetic number, because the mean of its divisors is an integer number (322764379).

Almost surely, 2^645528757 is an apocalyptic number.

It is an amenable number.

645528757 is a deficient number, since it is larger than the sum of its proper divisors (1).

645528757 is an equidigital number, since it uses as much as digits as its factorization.

645528757 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2352000, while the sum is 49.

The square root of 645528757 is about 25407.2579590951. The cubic root of 645528757 is about 864.2482947831.

The spelling of 645528757 in words is "six hundred forty-five million, five hundred twenty-eight thousand, seven hundred fifty-seven".