21857792 has 40 divisors (see below), whose sum is σ = 47655432. Its totient is φ = 9932800.

The previous prime is 21857779. The next prime is 21857807. The reversal of 21857792 is 29775812.

It is a super-2 number, since 2×21857792² = 955526142230528, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3692 + ... + 7572.

Almost surely, 2^21857792 is an apocalyptic number.

21857792 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21857792, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23827716).

21857792 is an abundant number, since it is smaller than the sum of its proper divisors (25797640).

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

21857792 is an equidigital number, since it uses as much as digits as its factorization.

21857792 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3910 (or 3894 counting only the distinct ones).

The product of its digits is 70560, while the sum is 41.

The square root of 21857792 is about 4675.2317589613. The cubic root of 21857792 is about 279.5988814278.

The spelling of 21857792 in words is "twenty-one million, eight hundred fifty-seven thousand, seven hundred ninety-two".