21940121 has 4 divisors (see below), whose sum is σ = 25074432. Its totient is φ = 18805812.

The previous prime is 21940111. The next prime is 21940151. The reversal of 21940121 is 12104912.

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.

It is a cyclic number.

It is not a de Polignac number, because 21940121 - 2¹⁰ = 21939097 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21940093 and 21940102.

It is not an unprimeable number, because it can be changed into a prime (21940111) 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, 1567145 + ... + 1567158.

It is an arithmetic number, because the mean of its divisors is an integer number (6268608).

Almost surely, 2^21940121 is an apocalyptic number.

It is an amenable number.

21940121 is a deficient number, since it is larger than the sum of its proper divisors (3134311).

21940121 is an equidigital number, since it uses as much as digits as its factorization.

21940121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3134310.

The product of its (nonzero) digits is 144, while the sum is 20.

The square root of 21940121 is about 4684.0282877028. The cubic root of 21940121 is about 279.9494849347.

The spelling of 21940121 in words is "twenty-one million, nine hundred forty thousand, one hundred twenty-one".