645434840 has 32 divisors (see below), whose sum is σ = 1459848960. Its totient is φ = 256819200.

The previous prime is 645434831. The next prime is 645434857. The reversal of 645434840 is 48434546.

645434840 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×645434840² = 833172265371651200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 645434794 and 645434803.

It is a congruent 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, 34601 + ... + 49880.

It is an arithmetic number, because the mean of its divisors is an integer number (45620280).

Almost surely, 2^645434840 is an apocalyptic number.

It is an amenable number.

645434840 is an abundant number, since it is smaller than the sum of its proper divisors (814414120).

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

645434840 is a wasteful number, since it uses less digits than its factorization.

645434840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84683 (or 84679 counting only the distinct ones).

The product of its (nonzero) digits is 184320, while the sum is 38.

The square root of 645434840 is about 25405.4096601492. The cubic root of 645434840 is about 864.2063800257.

The spelling of 645434840 in words is "six hundred forty-five million, four hundred thirty-four thousand, eight hundred forty".