16661616665615 has 16 divisors (see below), whose sum is σ = 20140533793728. Its totient is φ = 13231570442496.

The previous prime is 16661616665599. The next prime is 16661616665621. The reversal of 16661616665615 is 51656661616661.

It is a cyclic number.

It is not a de Polignac number, because 16661616665615 - 2⁴ = 16661616665599 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21660494 + ... + 22416516.

It is an arithmetic number, because the mean of its divisors is an integer number (1258783362108).

Almost surely, 2^{16661616665615} is an apocalyptic number.

16661616665615 is a deficient number, since it is larger than the sum of its proper divisors (3478917128113).

16661616665615 is a wasteful number, since it uses less digits than its factorization.

16661616665615 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 788338.

The product of its digits is 41990400, while the sum is 62.

The spelling of 16661616665615 in words is "sixteen trillion, six hundred sixty-one billion, six hundred sixteen million, six hundred sixty-five thousand, six hundred fifteen".