66218920 has 16 divisors (see below), whose sum is σ = 148992660. Its totient is φ = 26487552.

The previous prime is 66218903. The next prime is 66218921. The reversal of 66218920 is 2981266.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 65836996 + 381924 = 8114^2 + 618^2 .

It is not an unprimeable number, because it can be changed into a prime (66218921) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 827697 + ... + 827776.

Almost surely, 2^66218920 is an apocalyptic number.

It is an amenable number.

66218920 is an abundant number, since it is smaller than the sum of its proper divisors (82773740).

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

66218920 is a wasteful number, since it uses less digits than its factorization.

66218920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1655484 (or 1655480 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 34.

The square root of 66218920 is about 8137.5008448540. The cubic root of 66218920 is about 404.5703312947.

The spelling of 66218920 in words is "sixty-six million, two hundred eighteen thousand, nine hundred twenty".