21211392 has 72 divisors (see below), whose sum is σ = 57395520. Its totient is φ = 6952960.

The previous prime is 21211387. The next prime is 21211403. The reversal of 21211392 is 29311212.

It is a super-3 number, since 3×21211392³ (a number of 23 digits) contains 333 as substring.

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, 54334 + ... + 54722.

It is an arithmetic number, because the mean of its divisors is an integer number (797160).

Almost surely, 2^21211392 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 21211392, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28697760).

21211392 is an abundant number, since it is smaller than the sum of its proper divisors (36184128).

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

21211392 is an equidigital number, since it uses as much as digits as its factorization.

21211392 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 479 (or 465 counting only the distinct ones).

The product of its digits is 216, while the sum is 21.

The square root of 21211392 is about 4605.5826992901. The cubic root of 21211392 is about 276.8150659491.

The spelling of 21211392 in words is "twenty-one million, two hundred eleven thousand, three hundred ninety-two".