21187344 has 20 divisors (see below), whose sum is σ = 54734096. Its totient is φ = 7062432.

The previous prime is 21187339. The next prime is 21187349. The reversal of 21187344 is 44378112.

It is an interprime number because it is at equal distance from previous prime (21187339) and next prime (21187349).

It is not an unprimeable number, because it can be changed into a prime (21187349) 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, 220654 + ... + 220749.

Almost surely, 2^21187344 is an apocalyptic number.

21187344 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21187344 is an abundant number, since it is smaller than the sum of its proper divisors (33546752).

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

21187344 is a wasteful number, since it uses less digits than its factorization.

21187344 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 441414 (or 441408 counting only the distinct ones).

The product of its digits is 5376, while the sum is 30.

The square root of 21187344 is about 4602.9712143354. The cubic root of 21187344 is about 276.7104151718.

The spelling of 21187344 in words is "twenty-one million, one hundred eighty-seven thousand, three hundred forty-four".