66666604544 has 24 divisors (see below), whose sum is σ = 133300661130. Its totient is φ = 33333301248.

The previous prime is 66666604513. The next prime is 66666604619. The reversal of 66666604544 is 44540666666.

It can be written as a sum of positive squares in only one way, i.e., 52716160000 + 13950444544 = 229600^2 + 118112^2 .

It is a super-2 number, since 2×66666604544² (a number of 22 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16273979 + ... + 16278074.

Almost surely, 2^66666604544 is an apocalyptic number.

66666604544 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

66666604544 is a deficient number, since it is larger than the sum of its proper divisors (66634056586).

66666604544 is an equidigital number, since it uses as much as digits as its factorization.

66666604544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32552075 (or 32552055 counting only the distinct ones).

The product of its (nonzero) digits is 14929920, while the sum is 53.

The spelling of 66666604544 in words is "sixty-six billion, six hundred sixty-six million, six hundred four thousand, five hundred forty-four".