645560031 has 4 divisors (see below), whose sum is σ = 860746712. Its totient is φ = 430373352.

The previous prime is 645559991. The next prime is 645560143. The reversal of 645560031 is 130065546.

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

It is not a de Polignac number, because 645560031 - 2¹⁵ = 645527263 is a prime.

It is a super-2 number, since 2×645560031² = 833495507249441922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645560731) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 107593336 + ... + 107593341.

It is an arithmetic number, because the mean of its divisors is an integer number (215186678).

Almost surely, 2^645560031 is an apocalyptic number.

645560031 is a deficient number, since it is larger than the sum of its proper divisors (215186681).

645560031 is a wasteful number, since it uses less digits than its factorization.

645560031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215186680.

The product of its (nonzero) digits is 10800, while the sum is 30.

The square root of 645560031 is about 25407.8734056985. The cubic root of 645560031 is about 864.2622513339.

The spelling of 645560031 in words is "six hundred forty-five million, five hundred sixty thousand, thirty-one".