646401915 has 12 divisors (see below), whose sum is σ = 1120430064. Its totient is φ = 344747664.

The previous prime is 646401911. The next prime is 646401947. The reversal of 646401915 is 519104646.

646401915 is a `hidden beast` number, since 6 + 4 + 640 + 1 + 9 + 1 + 5 = 666.

It is not a de Polignac number, because 646401915 - 2² = 646401911 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 646401915.

It is not an unprimeable number, because it can be changed into a prime (646401911) 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, 7182199 + ... + 7182288.

It is an arithmetic number, because the mean of its divisors is an integer number (93369172).

Almost surely, 2^646401915 is an apocalyptic number.

646401915 is a deficient number, since it is larger than the sum of its proper divisors (474028149).

646401915 is a wasteful number, since it uses less digits than its factorization.

646401915 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14364498 (or 14364495 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The square root of 646401915 is about 25424.4353919610. The cubic root of 646401915 is about 864.6377870240.

The spelling of 646401915 in words is "six hundred forty-six million, four hundred one thousand, nine hundred fifteen".