21115392 has 80 divisors (see below), whose sum is σ = 57451680. Its totient is φ = 6889472.

The previous prime is 21115379. The next prime is 21115417. The reversal of 21115392 is 29351112.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 90508 + ... + 90740.

It is an arithmetic number, because the mean of its divisors is an integer number (718146).

Almost surely, 2^21115392 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 21115392, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28725840).

21115392 is an abundant number, since it is smaller than the sum of its proper divisors (36336288).

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

21115392 is an equidigital number, since it uses as much as digits as its factorization.

21115392 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 313 (or 297 counting only the distinct ones).

The product of its digits is 540, while the sum is 24.

The square root of 21115392 is about 4595.1487462323. The cubic root of 21115392 is about 276.3968246888.

It can be divided in two parts, 2111 and 5392, that added together give a triangular number (7503 = T₁₂₂).

The spelling of 21115392 in words is "twenty-one million, one hundred fifteen thousand, three hundred ninety-two".