15665116621989 has 24 divisors (see below), whose sum is σ = 22572410283072. Its totient is φ = 9644889358720.

The previous prime is 15665116621927. The next prime is 15665116621991. The reversal of 15665116621989 is 98912661156651.

It is not a de Polignac number, because 15665116621989 - 2³³ = 15656526687397 is a prime.

It is a super-2 number, since 2×15665116621989² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15665116625989) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 134918592 + ... + 135034649.

It is an arithmetic number, because the mean of its divisors is an integer number (940517095128).

Almost surely, 2^{15665116621989} is an apocalyptic number.

It is an amenable number.

15665116621989 is a deficient number, since it is larger than the sum of its proper divisors (6907293661083).

15665116621989 is a wasteful number, since it uses less digits than its factorization.

15665116621989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 269953325 (or 269953296 counting only the distinct ones).

The product of its digits is 41990400, while the sum is 66.

The spelling of 15665116621989 in words is "fifteen trillion, six hundred sixty-five billion, one hundred sixteen million, six hundred twenty-one thousand, nine hundred eighty-nine".