66659994 has 12 divisors (see below), whose sum is σ = 144430026. Its totient is φ = 22219992.

The previous prime is 66659993. The next prime is 66660059. The reversal of 66659994 is 49995666.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 65367225 + 1292769 = 8085^2 + 1137^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 66659994.

It is not an unprimeable number, because it can be changed into a prime (66659993) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1851649 + ... + 1851684.

Almost surely, 2^66659994 is an apocalyptic number.

66659994 is an abundant number, since it is smaller than the sum of its proper divisors (77770032).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66659994 is a wasteful number, since it uses less digits than its factorization.

66659994 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3703341 (or 3703338 counting only the distinct ones).

The product of its digits is 3149280, while the sum is 54.

The square root of 66659994 is about 8164.5571833382. The cubic root of 66659994 is about 405.4666044180.

The spelling of 66659994 in words is "sixty-six million, six hundred fifty-nine thousand, nine hundred ninety-four".