66015971522 has 18 divisors (see below), whose sum is σ = 100108795563. Its totient is φ = 32650255872.

The previous prime is 66015971509. The next prime is 66015971543. The reversal of 66015971522 is 22517951066.

It is a happy number.

It can be written as a sum of positive squares in 5 ways, for example, as 832264801 + 65183706721 = 28849^2 + 255311^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=181681.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 35245178 + ... + 35247050.

Almost surely, 2^66015971522 is an apocalyptic number.

66015971522 is a deficient number, since it is larger than the sum of its proper divisors (34092824041).

66015971522 is an frugal number, since it uses more digits than its factorization.

66015971522 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3942 (or 1972 counting only the distinct ones).

The product of its (nonzero) digits is 226800, while the sum is 44.

The spelling of 66015971522 in words is "sixty-six billion, fifteen million, nine hundred seventy-one thousand, five hundred twenty-two".