645563375 has 16 divisors (see below), whose sum is σ = 831657216. Its totient is φ = 499788000.

The previous prime is 645563353. The next prime is 645563381. The reversal of 645563375 is 573365546.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-645563375 is a prime.

It is a super-2 number, since 2×645563375² = 833504142282781250, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 79424 + ... + 87173.

It is an arithmetic number, because the mean of its divisors is an integer number (51978576).

Almost surely, 2^645563375 is an apocalyptic number.

645563375 is a deficient number, since it is larger than the sum of its proper divisors (186093841).

645563375 is a wasteful number, since it uses less digits than its factorization.

645563375 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166643 (or 166633 counting only the distinct ones).

The product of its digits is 1134000, while the sum is 44.

The square root of 645563375 is about 25407.9392119865. The cubic root of 645563375 is about 864.2637436237.

The spelling of 645563375 in words is "six hundred forty-five million, five hundred sixty-three thousand, three hundred seventy-five".