664841816 has 16 divisors (see below), whose sum is σ = 1246896240. Its totient is φ = 332336160.

The previous prime is 664841813. The next prime is 664841833. The reversal of 664841816 is 618148466.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664841813) 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, 33581 + ... + 49571.

It is an arithmetic number, because the mean of its divisors is an integer number (77931015).

Almost surely, 2^664841816 is an apocalyptic number.

It is an amenable number.

664841816 is a deficient number, since it is larger than the sum of its proper divisors (582054424).

664841816 is a wasteful number, since it uses less digits than its factorization.

664841816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21194 (or 21190 counting only the distinct ones).

The product of its digits is 221184, while the sum is 44.

The square root of 664841816 is about 25784.5266778353. The cubic root of 664841816 is about 872.7826594084.

The spelling of 664841816 in words is "six hundred sixty-four million, eight hundred forty-one thousand, eight hundred sixteen".