66213660 has 24 divisors (see below), whose sum is σ = 185398416. Its totient is φ = 17656960.

The previous prime is 66213659. The next prime is 66213671. The reversal of 66213660 is 6631266.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 551721 + ... + 551840.

It is an arithmetic number, because the mean of its divisors is an integer number (7724934).

Almost surely, 2^66213660 is an apocalyptic number.

66213660 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66213660 is an abundant number, since it is smaller than the sum of its proper divisors (119184756).

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

66213660 is a wasteful number, since it uses less digits than its factorization.

66213660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1103573 (or 1103571 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 30.

The square root of 66213660 is about 8137.1776433847. The cubic root of 66213660 is about 404.5596188665.

The spelling of 66213660 in words is "sixty-six million, two hundred thirteen thousand, six hundred sixty".