66657172 has 24 divisors (see below), whose sum is σ = 118752480. Its totient is φ = 32733600.

The previous prime is 66657137. The next prime is 66657179. The reversal of 66657172 is 27175666.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66657179) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 55563 + ... + 56749.

It is an arithmetic number, because the mean of its divisors is an integer number (4948020).

Almost surely, 2^66657172 is an apocalyptic number.

It is an amenable number.

66657172 is a deficient number, since it is larger than the sum of its proper divisors (52095308).

66657172 is a wasteful number, since it uses less digits than its factorization.

66657172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1431 (or 1429 counting only the distinct ones).

The product of its digits is 105840, while the sum is 40.

The square root of 66657172 is about 8164.3843613588. The cubic root of 66657172 is about 405.4608826308.

The spelling of 66657172 in words is "sixty-six million, six hundred fifty-seven thousand, one hundred seventy-two".