21571392 has 56 divisors (see below), whose sum is σ = 57420256. Its totient is φ = 7147008.

The previous prime is 21571367. The next prime is 21571397. The reversal of 21571392 is 29317512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21571397) 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, 54138 + ... + 54534.

Almost surely, 2^21571392 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 21571392, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28710128).

21571392 is an abundant number, since it is smaller than the sum of its proper divisors (35848864).

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

21571392 is a wasteful number, since it uses less digits than its factorization.

21571392 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 695 (or 685 counting only the distinct ones).

The product of its digits is 3780, while the sum is 30.

The square root of 21571392 is about 4644.5012649369. The cubic root of 21571392 is about 278.3723251655.

The spelling of 21571392 in words is "twenty-one million, five hundred seventy-one thousand, three hundred ninety-two".