645812913 has 8 divisors (see below), whose sum is σ = 871984000. Its totient is φ = 425091888.

The previous prime is 645812903. The next prime is 645812927. The reversal of 645812913 is 319218546.

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

It is not a de Polignac number, because 645812913 - 2¹⁰ = 645811889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645812903) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1362238 + ... + 1362711.

It is an arithmetic number, because the mean of its divisors is an integer number (108998000).

Almost surely, 2^645812913 is an apocalyptic number.

It is an amenable number.

645812913 is a deficient number, since it is larger than the sum of its proper divisors (226171087).

645812913 is a wasteful number, since it uses less digits than its factorization.

645812913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2725031.

The product of its digits is 51840, while the sum is 39.

The square root of 645812913 is about 25412.8493679871. The cubic root of 645812913 is about 864.3750876436.

The spelling of 645812913 in words is "six hundred forty-five million, eight hundred twelve thousand, nine hundred thirteen".