20221909921 has 4 divisors (see below), whose sum is σ = 21411434052. Its totient is φ = 19032385792.

The previous prime is 20221909913. The next prime is 20221909937. The reversal of 20221909921 is 12990912202.

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

It can be written as a sum of positive squares in 2 ways, for example, as 18674589025 + 1547320896 = 136655^2 + 39336^2 .

It is a cyclic number.

It is not a de Polignac number, because 20221909921 - 2³ = 20221909913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20221900921) 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, 594762040 + ... + 594762073.

It is an arithmetic number, because the mean of its divisors is an integer number (5352858513).

Almost surely, 2^20221909921 is an apocalyptic number.

It is an amenable number.

20221909921 is a deficient number, since it is larger than the sum of its proper divisors (1189524131).

20221909921 is a wasteful number, since it uses less digits than its factorization.

20221909921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1189524130.

The product of its (nonzero) digits is 11664, while the sum is 37.

The spelling of 20221909921 in words is "twenty billion, two hundred twenty-one million, nine hundred nine thousand, nine hundred twenty-one".