645513832 has 8 divisors (see below), whose sum is σ = 1210338450. Its totient is φ = 322756912.

The previous prime is 645513811. The next prime is 645513887. The reversal of 645513832 is 238315546.

It can be written as a sum of positive squares in only one way, i.e., 503284356 + 142229476 = 22434^2 + 11926^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a junction number, because it is equal to n+sod(n) for n = 645513791 and 645513800.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40344607 + ... + 40344622.

Almost surely, 2^645513832 is an apocalyptic number.

It is an amenable number.

645513832 is a deficient number, since it is larger than the sum of its proper divisors (564824618).

645513832 is a wasteful number, since it uses less digits than its factorization.

645513832 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80689235 (or 80689231 counting only the distinct ones).

The product of its digits is 86400, while the sum is 37.

The square root of 645513832 is about 25406.9642421128. The cubic root of 645513832 is about 864.2416340908.

The spelling of 645513832 in words is "six hundred forty-five million, five hundred thirteen thousand, eight hundred thirty-two".