66989172 has 12 divisors (see below), whose sum is σ = 156308096. Its totient is φ = 22329720.

The previous prime is 66989161. The next prime is 66989173. The reversal of 66989172 is 27198966.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66989173) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2791204 + ... + 2791227.

Almost surely, 2^66989172 is an apocalyptic number.

It is an amenable number.

66989172 is an abundant number, since it is smaller than the sum of its proper divisors (89318924).

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

66989172 is a wasteful number, since it uses less digits than its factorization.

66989172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5582438 (or 5582436 counting only the distinct ones).

The product of its digits is 326592, while the sum is 48.

The square root of 66989172 is about 8184.6913197750. The cubic root of 66989172 is about 406.1329290435.

It can be divided in two parts, 66989 and 172, that added together give a triangular number (67161 = T₃₆₆).

The spelling of 66989172 in words is "sixty-six million, nine hundred eighty-nine thousand, one hundred seventy-two".