66722593618 has 4 divisors (see below), whose sum is σ = 100083890430. Its totient is φ = 33361296808.

The previous prime is 66722593591. The next prime is 66722593627. The reversal of 66722593618 is 81639522766.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 54159994729 + 12562598889 = 232723^2 + 112083^2 .

It is a super-2 number, since 2×66722593618² (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, 16680648403 + ... + 16680648406.

Almost surely, 2^66722593618 is an apocalyptic number.

66722593618 is a deficient number, since it is larger than the sum of its proper divisors (33361296812).

66722593618 is a wasteful number, since it uses less digits than its factorization.

66722593618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33361296811.

The product of its digits is 6531840, while the sum is 55.

The spelling of 66722593618 in words is "sixty-six billion, seven hundred twenty-two million, five hundred ninety-three thousand, six hundred eighteen".