645603566 has 8 divisors (see below), whose sum is σ = 968625864. Its totient is φ = 322728280.

The previous prime is 645603559. The next prime is 645603593. The reversal of 645603566 is 665306546.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25025 + ... + 43788.

It is an arithmetic number, because the mean of its divisors is an integer number (121078233).

Almost surely, 2^645603566 is an apocalyptic number.

645603566 is a deficient number, since it is larger than the sum of its proper divisors (323022298).

645603566 is a wasteful number, since it uses less digits than its factorization.

645603566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73506.

The product of its (nonzero) digits is 388800, while the sum is 41.

The square root of 645603566 is about 25408.7301138802. The cubic root of 645603566 is about 864.2816788126.

The spelling of 645603566 in words is "six hundred forty-five million, six hundred three thousand, five hundred sixty-six".