66137720 has 64 divisors (see below), whose sum is σ = 164384640. Its totient is φ = 23747200.

The previous prime is 66137711. The next prime is 66137767. The reversal of 66137720 is 2773166.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 35615 + ... + 37425.

It is an arithmetic number, because the mean of its divisors is an integer number (2568510).

Almost surely, 2^66137720 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66137720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (82192320).

66137720 is an abundant number, since it is smaller than the sum of its proper divisors (98246920).

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

66137720 is a wasteful number, since it uses less digits than its factorization.

66137720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1916 (or 1912 counting only the distinct ones).

The product of its (nonzero) digits is 10584, while the sum is 32.

The square root of 66137720 is about 8132.5100676236. The cubic root of 66137720 is about 404.4048974691.

The spelling of 66137720 in words is "sixty-six million, one hundred thirty-seven thousand, seven hundred twenty".