66439388 has 12 divisors (see below), whose sum is σ = 118743072. Its totient is φ = 32512800.

The previous prime is 66439379. The next prime is 66439391. The reversal of 66439388 is 88393466.

It is a Harshad number since it is a multiple of its sum of digits (47).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 176513 + ... + 176888.

It is an arithmetic number, because the mean of its divisors is an integer number (9895256).

Almost surely, 2^66439388 is an apocalyptic number.

It is an amenable number.

66439388 is a deficient number, since it is larger than the sum of its proper divisors (52303684).

66439388 is a wasteful number, since it uses less digits than its factorization.

66439388 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 353452 (or 353450 counting only the distinct ones).

The product of its digits is 746496, while the sum is 47.

The square root of 66439388 is about 8151.0360077723. The cubic root of 66439388 is about 405.0188234913.

The spelling of 66439388 in words is "sixty-six million, four hundred thirty-nine thousand, three hundred eighty-eight".