21449231 has 2 divisors, whose sum is σ = 21449232. Its totient is φ = 21449230.

The previous prime is 21449227. The next prime is 21449251. The reversal of 21449231 is 13294412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21449231 - 2² = 21449227 is a prime.

It is a super-2 number, since 2×21449231² = 920139020982722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21449231.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21449201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10724615 + 10724616.

It is an arithmetic number, because the mean of its divisors is an integer number (10724616).

Almost surely, 2^21449231 is an apocalyptic number.

21449231 is a deficient number, since it is larger than the sum of its proper divisors (1).

21449231 is an equidigital number, since it uses as much as digits as its factorization.

21449231 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1728, while the sum is 26.

The square root of 21449231 is about 4631.3314500260. The cubic root of 21449231 is about 277.8458464238.

The spelling of 21449231 in words is "twenty-one million, four hundred forty-nine thousand, two hundred thirty-one".