646399899 has 32 divisors (see below), whose sum is σ = 971611200. Its totient is φ = 424684800.

The previous prime is 646399877. The next prime is 646399907. The reversal of 646399899 is 998993646.

646399899 is a `hidden beast` number, since 6 + 463 + 99 + 89 + 9 = 666.

It is not a de Polignac number, because 646399899 - 2⁵ = 646399867 is a prime.

It is not an unprimeable number, because it can be changed into a prime (646399799) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 798607 + ... + 799415.

It is an arithmetic number, because the mean of its divisors is an integer number (30362850).

Almost surely, 2^646399899 is an apocalyptic number.

646399899 is a deficient number, since it is larger than the sum of its proper divisors (325211301).

646399899 is a wasteful number, since it uses less digits than its factorization.

646399899 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1212 (or 1206 counting only the distinct ones).

The product of its digits is 22674816, while the sum is 63.

The square root of 646399899 is about 25424.3957450320. The cubic root of 646399899 is about 864.6368881449.

The spelling of 646399899 in words is "six hundred forty-six million, three hundred ninety-nine thousand, eight hundred ninety-nine".