66553820 has 24 divisors (see below), whose sum is σ = 140044128. Its totient is φ = 26568000.

The previous prime is 66553819. The next prime is 66553841. The reversal of 66553820 is 2835566.

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, 7745 + ... + 13895.

It is an arithmetic number, because the mean of its divisors is an integer number (5835172).

Almost surely, 2^66553820 is an apocalyptic number.

It is an amenable number.

66553820 is an abundant number, since it is smaller than the sum of its proper divisors (73490308).

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

66553820 is a wasteful number, since it uses less digits than its factorization.

66553820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6701 (or 6699 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 35.

The square root of 66553820 is about 8158.0524636705. The cubic root of 66553820 is about 405.2512184213.

The spelling of 66553820 in words is "sixty-six million, five hundred fifty-three thousand, eight hundred twenty".