21403392 has 108 divisors (see below), whose sum is σ = 60890760. Its totient is φ = 6666240.

The previous prime is 21403337. The next prime is 21403399. The reversal of 21403392 is 29330412.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21403399) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 690417 + ... + 690447.

Almost surely, 2^21403392 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 21403392, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30445380).

21403392 is an abundant number, since it is smaller than the sum of its proper divisors (39487368).

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

21403392 is an equidigital number, since it uses as much as digits as its factorization.

21403392 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110 (or 65 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 24.

The square root of 21403392 is about 4626.3800103321. The cubic root of 21403392 is about 277.6477777947.

The spelling of 21403392 in words is "twenty-one million, four hundred three thousand, three hundred ninety-two".