816656666 has 16 divisors (see below), whose sum is σ = 1400402304. Its totient is φ = 349890864.

The previous prime is 816656639. The next prime is 816656683. The reversal of 816656666 is 666656618.

It is a super-2 number, since 2×816656666² = 1333856220244471112, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 56411 + ... + 69393.

It is an arithmetic number, because the mean of its divisors is an integer number (87525144).

Almost surely, 2^816656666 is an apocalyptic number.

816656666 is a deficient number, since it is larger than the sum of its proper divisors (583745638).

816656666 is a wasteful number, since it uses less digits than its factorization.

816656666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17485.

The product of its digits is 1866240, while the sum is 50.

The square root of 816656666 is about 28577.2053567174. The cubic root of 816656666 is about 934.7163450798.

The spelling of 816656666 in words is "eight hundred sixteen million, six hundred fifty-six thousand, six hundred sixty-six".