21244405 has 16 divisors (see below), whose sum is σ = 31377024. Its totient is φ = 13446720.

The previous prime is 21244369. The next prime is 21244417. The reversal of 21244405 is 50444212.

It is a happy number.

It is not a de Polignac number, because 21244405 - 2⁷ = 21244277 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22891 + ... + 23800.

It is an arithmetic number, because the mean of its divisors is an integer number (1961064).

Almost surely, 2^21244405 is an apocalyptic number.

It is an amenable number.

21244405 is a deficient number, since it is larger than the sum of its proper divisors (10132619).

21244405 is a wasteful number, since it uses less digits than its factorization.

21244405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46716.

The product of its (nonzero) digits is 1280, while the sum is 22.

The square root of 21244405 is about 4609.1653257396. The cubic root of 21244405 is about 276.9586013800.

Adding to 21244405 its reverse (50444212), we get a palindrome (71688617).

The spelling of 21244405 in words is "twenty-one million, two hundred forty-four thousand, four hundred five".