21224401 has 16 divisors (see below), whose sum is σ = 24069888. Its totient is φ = 18547200.

The previous prime is 21224389. The next prime is 21224431. The reversal of 21224401 is 10442212.

It is a cyclic number.

It is not a de Polignac number, because 21224401 - 2⁹ = 21223889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21224431) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 31201 + ... + 31873.

It is an arithmetic number, because the mean of its divisors is an integer number (1504368).

It is a Poulet number, since it divides 2^21224400-1.

Almost surely, 2^21224401 is an apocalyptic number.

It is an amenable number.

21224401 is a deficient number, since it is larger than the sum of its proper divisors (2845487).

21224401 is a wasteful number, since it uses less digits than its factorization.

21224401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 792.

The product of its (nonzero) digits is 128, while the sum is 16.

The square root of 21224401 is about 4606.9947905332. The cubic root of 21224401 is about 276.8716448425.

Adding to 21224401 its reverse (10442212), we get a palindrome (31666613).

It can be divided in two parts, 21 and 224401, that added together give a palindrome (224422).

The spelling of 21224401 in words is "twenty-one million, two hundred twenty-four thousand, four hundred one".