21331072 has 96 divisors (see below), whose sum is σ = 52326000. Its totient is φ = 8612352.

The previous prime is 21331067. The next prime is 21331081. The reversal of 21331072 is 27013312.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 119079 + ... + 119257.

Almost surely, 2^21331072 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 21331072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26163000).

21331072 is an abundant number, since it is smaller than the sum of its proper divisors (30994928).

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

21331072 is a wasteful number, since it uses less digits than its factorization.

21331072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 226 (or 207 counting only the distinct ones).

The product of its (nonzero) digits is 252, while the sum is 19.

The square root of 21331072 is about 4618.5573505154. The cubic root of 21331072 is about 277.3347098880.

Adding to 21331072 its reverse (27013312), we get a palindrome (48344384).

The spelling of 21331072 in words is "twenty-one million, three hundred thirty-one thousand, seventy-two".