21268992 has 80 divisors (see below), whose sum is σ = 57844512. Its totient is φ = 6942720.

The previous prime is 21268991. The next prime is 21268993. The reversal of 21268992 is 29986212.

It is an interprime number because it is at equal distance from previous prime (21268991) and next prime (21268993).

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors.

It is a zygodrome in base 11.

It is a self number, because there is not a number n which added to its sum of digits gives 21268992.

It is not an unprimeable number, because it can be changed into a prime (21268991) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 93583 + ... + 93809.

Almost surely, 2^21268992 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 21268992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28922256).

21268992 is an abundant number, since it is smaller than the sum of its proper divisors (36575520).

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

21268992 is an equidigital number, since it uses as much as digits as its factorization.

21268992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 309 (or 293 counting only the distinct ones).

The product of its digits is 31104, while the sum is 39.

The square root of 21268992 is about 4611.8317402091. The cubic root of 21268992 is about 277.0654052784.

The spelling of 21268992 in words is "twenty-one million, two hundred sixty-eight thousand, nine hundred ninety-two".