66431656 has 8 divisors (see below), whose sum is σ = 124559370. Its totient is φ = 33215824.

The previous prime is 66431611. The next prime is 66431669. The reversal of 66431656 is 65613466.

It can be written as a sum of positive squares in only one way, i.e., 44435556 + 21996100 = 6666^2 + 4690^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a hoax number, since the sum of its digits (37) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4151971 + ... + 4151986.

Almost surely, 2^66431656 is an apocalyptic number.

It is an amenable number.

66431656 is a deficient number, since it is larger than the sum of its proper divisors (58127714).

66431656 is a wasteful number, since it uses less digits than its factorization.

66431656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8303963 (or 8303959 counting only the distinct ones).

The product of its digits is 77760, while the sum is 37.

The square root of 66431656 is about 8150.5616984353. The cubic root of 66431656 is about 405.0031112904.

The spelling of 66431656 in words is "sixty-six million, four hundred thirty-one thousand, six hundred fifty-six".