66561364 has 18 divisors (see below), whose sum is σ = 118181882. Its totient is φ = 32802000.

The previous prime is 66561359. The next prime is 66561373. The reversal of 66561364 is 46316566.

66561364 = 17² + 18² + ... + 584².

It can be written as a sum of positive squares in only one way, i.e., 48413764 + 18147600 = 6958^2 + 4260^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 18514 + ... + 21814.

Almost surely, 2^66561364 is an apocalyptic number.

It is an amenable number.

66561364 is a deficient number, since it is larger than the sum of its proper divisors (51620518).

66561364 is a wasteful number, since it uses less digits than its factorization.

66561364 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3447 (or 3374 counting only the distinct ones).

The product of its digits is 77760, while the sum is 37.

The square root of 66561364 is about 8158.5148158228. The cubic root of 66561364 is about 405.2665298373.

The spelling of 66561364 in words is "sixty-six million, five hundred sixty-one thousand, three hundred sixty-four".