21853902 has 80 divisors (see below), whose sum is σ = 53644752. Its totient is φ = 5927040.

The previous prime is 21853889. The next prime is 21853913. The reversal of 21853902 is 20935812.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21853902.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 533002 + ... + 533042.

Almost surely, 2^21853902 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21853902, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26822376).

21853902 is an abundant number, since it is smaller than the sum of its proper divisors (31790850).

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

21853902 is an equidigital number, since it uses as much as digits as its factorization.

21853902 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111 (or 90 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 30.

The square root of 21853902 is about 4674.8157182931. The cubic root of 21853902 is about 279.5822938393.

The spelling of 21853902 in words is "twenty-one million, eight hundred fifty-three thousand, nine hundred two".