66515772616 has 8 divisors (see below), whose sum is σ = 124717073670. Its totient is φ = 33257886304.

The previous prime is 66515772601. The next prime is 66515772623. The reversal of 66515772616 is 61627751566.

66515772616 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 51424632900 + 15091139716 = 226770^2 + 122846^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4157235781 + ... + 4157235796.

Almost surely, 2^66515772616 is an apocalyptic number.

It is an amenable number.

66515772616 is a deficient number, since it is larger than the sum of its proper divisors (58201301054).

66515772616 is a wasteful number, since it uses less digits than its factorization.

66515772616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8314471583 (or 8314471579 counting only the distinct ones).

The product of its digits is 3175200, while the sum is 52.

The spelling of 66515772616 in words is "sixty-six billion, five hundred fifteen million, seven hundred seventy-two thousand, six hundred sixteen".