21497344 has 60 divisors (see below), whose sum is σ = 47348532. Its totient is φ = 9743360.

The previous prime is 21497339. The next prime is 21497351. The reversal of 21497344 is 44379412.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 61779 + ... + 62125.

Almost surely, 2^21497344 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21497344, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23674266).

21497344 is an abundant number, since it is smaller than the sum of its proper divisors (25851188).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21497344 is an equidigital number, since it uses as much as digits as its factorization.

21497344 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 387 (or 360 counting only the distinct ones).

The product of its digits is 24192, while the sum is 34.

The square root of 21497344 is about 4636.5228350565. The cubic root of 21497344 is about 278.0534376166.

The spelling of 21497344 in words is "twenty-one million, four hundred ninety-seven thousand, three hundred forty-four".