21921441 has 4 divisors (see below), whose sum is σ = 29228592. Its totient is φ = 14614292.

The previous prime is 21921437. The next prime is 21921451. The reversal of 21921441 is 14412912.

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 21921441 - 2² = 21921437 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21921451) 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, 3653571 + ... + 3653576.

It is an arithmetic number, because the mean of its divisors is an integer number (7307148).

Almost surely, 2^21921441 is an apocalyptic number.

It is an amenable number.

21921441 is a deficient number, since it is larger than the sum of its proper divisors (7307151).

21921441 is an equidigital number, since it uses as much as digits as its factorization.

21921441 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7307150.

The product of its digits is 576, while the sum is 24.

The square root of 21921441 is about 4682.0338529319. The cubic root of 21921441 is about 279.8700119422.

The spelling of 21921441 in words is "twenty-one million, nine hundred twenty-one thousand, four hundred forty-one".