21220999967 has 4 divisors (see below), whose sum is σ = 21221742960. Its totient is φ = 21220256976.

The previous prime is 21220999963. The next prime is 21220999973. The reversal of 21220999967 is 76999902212.

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 21220999967 - 2² = 21220999963 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21220999963) 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, 326867 + ... + 386372.

It is an arithmetic number, because the mean of its divisors is an integer number (5305435740).

Almost surely, 2^21220999967 is an apocalyptic number.

21220999967 is a deficient number, since it is larger than the sum of its proper divisors (742993).

21220999967 is an equidigital number, since it uses as much as digits as its factorization.

21220999967 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 742992.

The product of its (nonzero) digits is 2204496, while the sum is 56.

The spelling of 21220999967 in words is "twenty-one billion, two hundred twenty million, nine hundred ninety-nine thousand, nine hundred sixty-seven".