66939964 has 48 divisors (see below), whose sum is σ = 151782400. Its totient is φ = 25085376.

The previous prime is 66939953. The next prime is 66939973. The reversal of 66939964 is 46993966.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (52).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2077 + ... + 11755.

Almost surely, 2^66939964 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 66939964, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (75891200).

66939964 is an abundant number, since it is smaller than the sum of its proper divisors (84842436).

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

66939964 is a wasteful number, since it uses less digits than its factorization.

66939964 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9722 (or 9720 counting only the distinct ones).

The product of its digits is 1889568, while the sum is 52.

The square root of 66939964 is about 8181.6846675975. The cubic root of 66939964 is about 406.0334608060.

The spelling of 66939964 in words is "sixty-six million, nine hundred thirty-nine thousand, nine hundred sixty-four".