22021921 has 4 divisors (see below), whose sum is σ = 22034992. Its totient is φ = 22008852.

The previous prime is 22021913. The next prime is 22021943. The reversal of 22021921 is 12912022.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12912022 = 2 ⋅6456011.

It is a cyclic number.

It is not a de Polignac number, because 22021921 - 2³ = 22021913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (22021981) 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, 3555 + ... + 7528.

It is an arithmetic number, because the mean of its divisors is an integer number (5508748).

Almost surely, 2^22021921 is an apocalyptic number.

It is an amenable number.

22021921 is a deficient number, since it is larger than the sum of its proper divisors (13071).

22021921 is a wasteful number, since it uses less digits than its factorization.

22021921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13070.

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

The square root of 22021921 is about 4692.7519644661. The cubic root of 22021921 is about 280.2969680875.

Adding to 22021921 its reverse (12912022), we get a palindrome (34933943).

The spelling of 22021921 in words is "twenty-two million, twenty-one thousand, nine hundred twenty-one".