66699904 has 32 divisors (see below), whose sum is σ = 133293600. Its totient is φ = 33245952.

The previous prime is 66699847. The next prime is 66699949. The reversal of 66699904 is 40999666.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (32).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55599 + ... + 56785.

It is an arithmetic number, because the mean of its divisors is an integer number (4165425).

Almost surely, 2^66699904 is an apocalyptic number.

66699904 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

66699904 is a deficient number, since it is larger than the sum of its proper divisors (66593696).

66699904 is a wasteful number, since it uses less digits than its factorization.

66699904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1640 (or 1628 counting only the distinct ones).

The product of its (nonzero) digits is 629856, while the sum is 49.

The square root of 66699904 is about 8167.0009183298. Note that the first 3 decimals coincide. The cubic root of 66699904 is about 405.5475072345.

The spelling of 66699904 in words is "sixty-six million, six hundred ninety-nine thousand, nine hundred four".