21628992 has 252 divisors, whose sum is σ = 77022960. Its totient is φ = 5322240.

The previous prime is 21628969. The next prime is 21629009. The reversal of 21628992 is 29982612.

It is a self number, because there is not a number n which added to its sum of digits gives 21628992.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1138359 + ... + 1138377.

Almost surely, 2^21628992 is an apocalyptic number.

21628992 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 21628992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38511480).

21628992 is an abundant number, since it is smaller than the sum of its proper divisors (55393968).

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

21628992 is a wasteful number, since it uses less digits than its factorization.

21628992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70 (or 42 counting only the distinct ones).

The product of its digits is 31104, while the sum is 39.

The square root of 21628992 is about 4650.6980121268. The cubic root of 21628992 is about 278.6198751845.

The spelling of 21628992 in words is "twenty-one million, six hundred twenty-eight thousand, nine hundred ninety-two".