645500643 has 16 divisors (see below), whose sum is σ = 866695296. Its totient is φ = 427331520.

The previous prime is 645500599. The next prime is 645500657. The reversal of 645500643 is 346005546.

It is not a de Polignac number, because 645500643 - 2⁹ = 645500131 is a prime.

It is a super-2 number, since 2×645500643² = 833342160226826898, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (645500683) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 279871 + ... + 282167.

It is an arithmetic number, because the mean of its divisors is an integer number (54168456).

Almost surely, 2^645500643 is an apocalyptic number.

645500643 is a deficient number, since it is larger than the sum of its proper divisors (221194653).

645500643 is a wasteful number, since it uses less digits than its factorization.

645500643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2914.

The product of its (nonzero) digits is 43200, while the sum is 33.

The square root of 645500643 is about 25406.7046859682. The cubic root of 645500643 is about 864.2357480509.

The spelling of 645500643 in words is "six hundred forty-five million, five hundred thousand, six hundred forty-three".