21164111656 has 16 divisors (see below), whose sum is σ = 40527023040. Its totient is φ = 10356905520.

The previous prime is 21164111611. The next prime is 21164111671. The reversal of 21164111656 is 65611146112.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 28143390 + ... + 28144141.

It is an arithmetic number, because the mean of its divisors is an integer number (2532938940).

Almost surely, 2^21164111656 is an apocalyptic number.

It is an amenable number.

21164111656 is a deficient number, since it is larger than the sum of its proper divisors (19362911384).

21164111656 is a wasteful number, since it uses less digits than its factorization.

21164111656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56287584 (or 56287580 counting only the distinct ones).

The product of its digits is 8640, while the sum is 34.

Adding to 21164111656 its reverse (65611146112), we get a palindrome (86775257768).

The spelling of 21164111656 in words is "twenty-one billion, one hundred sixty-four million, one hundred eleven thousand, six hundred fifty-six".