21449397 has 4 divisors (see below), whose sum is σ = 28599200. Its totient is φ = 14299596.

The previous prime is 21449387. The next prime is 21449413. The reversal of 21449397 is 79394412.

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 not a de Polignac number, because 21449397 - 2²² = 17255093 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21449387) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3574897 + ... + 3574902.

It is an arithmetic number, because the mean of its divisors is an integer number (7149800).

Almost surely, 2^21449397 is an apocalyptic number.

It is an amenable number.

21449397 is a deficient number, since it is larger than the sum of its proper divisors (7149803).

21449397 is an equidigital number, since it uses as much as digits as its factorization.

21449397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7149802.

The product of its digits is 54432, while the sum is 39.

The square root of 21449397 is about 4631.3493714035. The cubic root of 21449397 is about 277.8465631906.

The spelling of 21449397 in words is "twenty-one million, four hundred forty-nine thousand, three hundred ninety-seven".