645540544 has 28 divisors (see below), whose sum is σ = 1397450088. Its totient is φ = 293427200.

The previous prime is 645540481. The next prime is 645540587. The reversal of 645540544 is 445045546.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 457777 + ... + 459184.

Almost surely, 2^645540544 is an apocalyptic number.

645540544 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

645540544 is an abundant number, since it is smaller than the sum of its proper divisors (751909544).

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

645540544 is a wasteful number, since it uses less digits than its factorization.

645540544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 916984 (or 916974 counting only the distinct ones).

The product of its (nonzero) digits is 192000, while the sum is 37.

The square root of 645540544 is about 25407.4899193132. The cubic root of 645540544 is about 864.2535549839.

The spelling of 645540544 in words is "six hundred forty-five million, five hundred forty thousand, five hundred forty-four".