645104555 has 4 divisors (see below), whose sum is σ = 774125472. Its totient is φ = 516083640.

The previous prime is 645104531. The next prime is 645104569. The reversal of 645104555 is 555401546.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 645104555 - 2²⁸ = 376669099 is a prime.

It is a Duffinian 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, 64510451 + ... + 64510460.

It is an arithmetic number, because the mean of its divisors is an integer number (193531368).

Almost surely, 2^645104555 is an apocalyptic number.

645104555 is a deficient number, since it is larger than the sum of its proper divisors (129020917).

645104555 is a wasteful number, since it uses less digits than its factorization.

645104555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129020916.

The product of its (nonzero) digits is 60000, while the sum is 35.

The square root of 645104555 is about 25398.9085395416. The cubic root of 645104555 is about 864.0589429345.

The spelling of 645104555 in words is "six hundred forty-five million, one hundred four thousand, five hundred fifty-five".