66218820 has 48 divisors (see below), whose sum is σ = 186193728. Its totient is φ = 17584000.

The previous prime is 66218809. The next prime is 66218849. The reversal of 66218820 is 2881266.

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, 12862 + ... + 17258.

It is an arithmetic number, because the mean of its divisors is an integer number (3879036).

Almost surely, 2^66218820 is an apocalyptic number.

66218820 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66218820 is an abundant number, since it is smaller than the sum of its proper divisors (119974908).

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

66218820 is a wasteful number, since it uses less digits than its factorization.

66218820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4660 (or 4658 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 33.

The square root of 66218820 is about 8137.4947004591. The cubic root of 66218820 is about 404.5701276417.

The spelling of 66218820 in words is "sixty-six million, two hundred eighteen thousand, eight hundred twenty".