646191888 has 20 divisors (see below), whose sum is σ = 1669329168. Its totient is φ = 215397280.

The previous prime is 646191841. The next prime is 646191899. The reversal of 646191888 is 888191646.

It is a super-2 number, since 2×646191888² = 835127912234009088, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 646191888.

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, 6731118 + ... + 6731213.

Almost surely, 2^646191888 is an apocalyptic number.

It is an amenable number.

646191888 is an abundant number, since it is smaller than the sum of its proper divisors (1023137280).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

646191888 is a wasteful number, since it uses less digits than its factorization.

646191888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13462342 (or 13462336 counting only the distinct ones).

The product of its digits is 663552, while the sum is 51.

The square root of 646191888 is about 25420.3046401887. The cubic root of 646191888 is about 864.5441316950.

The spelling of 646191888 in words is "six hundred forty-six million, one hundred ninety-one thousand, eight hundred eighty-eight".