642658815 has 12 divisors (see below), whose sum is σ = 1113942024. Its totient is φ = 342751344.

The previous prime is 642658789. The next prime is 642658817. The reversal of 642658815 is 518856246.

642658815 is a `hidden beast` number, since 64 + 2 + 6 + 588 + 1 + 5 = 666.

It is not a de Polignac number, because 642658815 - 2¹⁶ = 642593279 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 14281307 = 642658815 / (6 + 4 + 2 + 6 + 5 + 8 + 8 + 1 + 5).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642658817) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7140609 + ... + 7140698.

It is an arithmetic number, because the mean of its divisors is an integer number (92828502).

Almost surely, 2^642658815 is an apocalyptic number.

642658815 is a deficient number, since it is larger than the sum of its proper divisors (471283209).

642658815 is a wasteful number, since it uses less digits than its factorization.

642658815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14281318 (or 14281315 counting only the distinct ones).

The product of its digits is 460800, while the sum is 45.

The square root of 642658815 is about 25350.7162620704. The cubic root of 642658815 is about 862.9656112335.

The spelling of 642658815 in words is "six hundred forty-two million, six hundred fifty-eight thousand, eight hundred fifteen".