645857552 has 10 divisors (see below), whose sum is σ = 1251349038. Its totient is φ = 322928768.

The previous prime is 645857551. The next prime is 645857561. The reversal of 645857552 is 255758546.

It can be written as a sum of positive squares in only one way, i.e., 635846656 + 10010896 = 25216^2 + 3164^2 .

It is a junction number, because it is equal to n+sod(n) for n = 645857497 and 645857506.

It is not an unprimeable number, because it can be changed into a prime (645857551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20183033 + ... + 20183064.

Almost surely, 2^645857552 is an apocalyptic number.

It is an amenable number.

645857552 is a deficient number, since it is larger than the sum of its proper divisors (605491486).

645857552 is a wasteful number, since it uses less digits than its factorization.

645857552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40366105 (or 40366099 counting only the distinct ones).

The product of its digits is 1680000, while the sum is 47.

The square root of 645857552 is about 25413.7276289804. The cubic root of 645857552 is about 864.3950025704.

The spelling of 645857552 in words is "six hundred forty-five million, eight hundred fifty-seven thousand, five hundred fifty-two".