646496881 has 4 divisors (see below), whose sum is σ = 646582500. Its totient is φ = 646411264.

The previous prime is 646496839. The next prime is 646496947. The reversal of 646496881 is 188694646.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 163200625 + 483296256 = 12775^2 + 21984^2 .

It is a cyclic number.

It is not a de Polignac number, because 646496881 - 2⁹ = 646496369 is a prime.

It is a super-2 number, since 2×646496881² = 835916434285456322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (646496821) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30256 + ... + 46993.

It is an arithmetic number, because the mean of its divisors is an integer number (161645625).

Almost surely, 2^646496881 is an apocalyptic number.

It is an amenable number.

646496881 is a deficient number, since it is larger than the sum of its proper divisors (85619).

646496881 is an equidigital number, since it uses as much as digits as its factorization.

646496881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85618.

The product of its digits is 1990656, while the sum is 52.

The square root of 646496881 is about 25426.3029361329. The cubic root of 646496881 is about 864.6801276428.

The spelling of 646496881 in words is "six hundred forty-six million, four hundred ninety-six thousand, eight hundred eighty-one".