66138860 has 12 divisors (see below), whose sum is σ = 138891648. Its totient is φ = 26455536.

The previous prime is 66138851. The next prime is 66138871. The reversal of 66138860 is 6883166.

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, 1653452 + ... + 1653491.

It is an arithmetic number, because the mean of its divisors is an integer number (11574304).

Almost surely, 2^66138860 is an apocalyptic number.

It is an amenable number.

66138860 is an abundant number, since it is smaller than the sum of its proper divisors (72752788).

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

66138860 is a wasteful number, since it uses less digits than its factorization.

66138860 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3306952 (or 3306950 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 38.

The square root of 66138860 is about 8132.5801563833. The cubic root of 66138860 is about 404.4072209992.

The spelling of 66138860 in words is "sixty-six million, one hundred thirty-eight thousand, eight hundred sixty".