21968228651 has 4 divisors (see below), whose sum is σ = 21980360904. Its totient is φ = 21956096400.

The previous prime is 21968228629. The next prime is 21968228657. The reversal of 21968228651 is 15682286912.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21968228651 - 2¹⁴ = 21968212267 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21968228651.

It is not an unprimeable number, because it can be changed into a prime (21968228657) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6063410 + ... + 6067031.

It is an arithmetic number, because the mean of its divisors is an integer number (5495090226).

Almost surely, 2^21968228651 is an apocalyptic number.

21968228651 is a deficient number, since it is larger than the sum of its proper divisors (12132253).

21968228651 is a wasteful number, since it uses less digits than its factorization.

21968228651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12132252.

The product of its digits is 829440, while the sum is 50.

The spelling of 21968228651 in words is "twenty-one billion, nine hundred sixty-eight million, two hundred twenty-eight thousand, six hundred fifty-one".