20221921 has 2 divisors, whose sum is σ = 20221922. Its totient is φ = 20221920.

The previous prime is 20221913. The next prime is 20221931. The reversal of 20221921 is 12912202.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16851025 + 3370896 = 4105^2 + 1836^2 .

It is a cyclic number.

It is not a de Polignac number, because 20221921 - 2³ = 20221913 is a prime.

It is not a weakly prime, because it can be changed into another prime (20221931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10110960 + 10110961.

It is an arithmetic number, because the mean of its divisors is an integer number (10110961).

Almost surely, 2^20221921 is an apocalyptic number.

It is an amenable number.

20221921 is a deficient number, since it is larger than the sum of its proper divisors (1).

20221921 is an equidigital number, since it uses as much as digits as its factorization.

20221921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 20221921 is about 4496.8790288377. The cubic root of 20221921 is about 272.4420481090.

The spelling of 20221921 in words is "twenty million, two hundred twenty-one thousand, nine hundred twenty-one".