21451392 has 80 divisors (see below), whose sum is σ = 63869850. Its totient is φ = 7147008.

The previous prime is 21451373. The next prime is 21451427. The reversal of 21451392 is 29315412.

It can be written as a sum of positive squares in only one way, i.e., 20575296 + 876096 = 4536^2 + 936^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 9334 + ... + 11402.

Almost surely, 2^21451392 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 21451392, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31934925).

21451392 is an abundant number, since it is smaller than the sum of its proper divisors (42418458).

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

21451392 is an equidigital number, since it uses as much as digits as its factorization.

21451392 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2095 (or 2074 counting only the distinct ones).

The product of its digits is 2160, while the sum is 27.

The square root of 21451392 is about 4631.5647463897. The cubic root of 21451392 is about 277.8551770568.

The spelling of 21451392 in words is "twenty-one million, four hundred fifty-one thousand, three hundred ninety-two".