21122401 has 4 divisors (see below), whose sum is σ = 21163312. Its totient is φ = 21081492.

The previous prime is 21122399. The next prime is 21122419. The reversal of 21122401 is 10422112.

It is a happy number.

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 21122401 - 2¹ = 21122399 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21122201) 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, 19671 + ... + 20716.

It is an arithmetic number, because the mean of its divisors is an integer number (5290828).

Almost surely, 2^21122401 is an apocalyptic number.

It is an amenable number.

21122401 is a deficient number, since it is larger than the sum of its proper divisors (40911).

21122401 is an equidigital number, since it uses as much as digits as its factorization.

21122401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40910.

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 21122401 is about 4595.9113350890. The cubic root of 21122401 is about 276.4274035044.

Adding to 21122401 its reverse (10422112), we get a palindrome (31544513).

The spelling of 21122401 in words is "twenty-one million, one hundred twenty-two thousand, four hundred one".