645473520 has 60 divisors (see below), whose sum is σ = 2167717656. Its totient is φ = 172126080.

The previous prime is 645473497. The next prime is 645473531. The reversal of 645473520 is 25374546.

645473520 is a `hidden beast` number, since 64 + 5 + 4 + 73 + 520 = 666.

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 447526 + ... + 448965.

Almost surely, 2^645473520 is an apocalyptic number.

645473520 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

645473520 is an abundant number, since it is smaller than the sum of its proper divisors (1522244136).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

645473520 is a wasteful number, since it uses less digits than its factorization.

645473520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 896510 (or 896501 counting only the distinct ones).

The product of its (nonzero) digits is 100800, while the sum is 36.

The square root of 645473520 is about 25406.1709039359. The cubic root of 645473520 is about 864.2236432375.

The spelling of 645473520 in words is "six hundred forty-five million, four hundred seventy-three thousand, five hundred twenty".