645957625 has 8 divisors (see below), whose sum is σ = 806155272. Its totient is φ = 516766000.

The previous prime is 645957617. The next prime is 645957647. The reversal of 645957625 is 526759546.

It can be written as a sum of positive squares in 4 ways, for example, as 4652649 + 641304976 = 2157^2 + 25324^2 .

It is not a de Polignac number, because 645957625 - 2³ = 645957617 is a prime.

It is a super-2 number, since 2×645957625² = 834522506591281250, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2583706 + ... + 2583955.

It is an arithmetic number, because the mean of its divisors is an integer number (100769409).

Almost surely, 2^645957625 is an apocalyptic number.

It is an amenable number.

645957625 is a deficient number, since it is larger than the sum of its proper divisors (160197647).

645957625 is an equidigital number, since it uses as much as digits as its factorization.

645957625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5167676 (or 5167666 counting only the distinct ones).

The product of its digits is 2268000, while the sum is 49.

The square root of 645957625 is about 25415.6964295689. The cubic root of 645957625 is about 864.4396450943.

The spelling of 645957625 in words is "six hundred forty-five million, nine hundred fifty-seven thousand, six hundred twenty-five".