21115562697 has 12 divisors (see below), whose sum is σ = 30719685360. Its totient is φ = 13975767288.

The previous prime is 21115562693. The next prime is 21115562719. The reversal of 21115562697 is 79626551112.

It is a happy number.

21115562697 is a `hidden beast` number, since 2 + 1 + 1 + 1 + 556 + 2 + 6 + 97 = 666.

It is not a de Polignac number, because 21115562697 - 2² = 21115562693 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21115562693) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8438223 + ... + 8440724.

It is an arithmetic number, because the mean of its divisors is an integer number (2559973780).

Almost surely, 2^21115562697 is an apocalyptic number.

It is an amenable number.

21115562697 is a deficient number, since it is larger than the sum of its proper divisors (9604122663).

21115562697 is a wasteful number, since it uses less digits than its factorization.

21115562697 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16879092 (or 16879089 counting only the distinct ones).

The product of its digits is 226800, while the sum is 45.

The spelling of 21115562697 in words is "twenty-one billion, one hundred fifteen million, five hundred sixty-two thousand, six hundred ninety-seven".