646465491 has 48 divisors (see below), whose sum is σ = 1097853120. Its totient is φ = 358871040.

The previous prime is 646465487. The next prime is 646465493. The reversal of 646465491 is 194564646.

It is a happy number.

646465491 is a `hidden beast` number, since 64 + 6 + 46 + 549 + 1 = 666.

It is not a de Polignac number, because 646465491 - 2² = 646465487 is a prime.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (646465493) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 911445 + ... + 912153.

It is an arithmetic number, because the mean of its divisors is an integer number (22871940).

Almost surely, 2^646465491 is an apocalyptic number.

646465491 is a deficient number, since it is larger than the sum of its proper divisors (451387629).

646465491 is a wasteful number, since it uses less digits than its factorization.

646465491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1116 (or 1113 counting only the distinct ones).

The product of its digits is 622080, while the sum is 45.

The square root of 646465491 is about 25425.6856544715. The cubic root of 646465491 is about 864.6661328610. Note that the first 3 decimals are identical.

The spelling of 646465491 in words is "six hundred forty-six million, four hundred sixty-five thousand, four hundred ninety-one".