21895830 has 96 divisors (see below), whose sum is σ = 65808288. Its totient is φ = 4992000.

The previous prime is 21895829. The next prime is 21895859. The reversal of 21895830 is 3859812.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 16180 + ... + 17480.

It is an arithmetic number, because the mean of its divisors is an integer number (685503).

Almost surely, 2^21895830 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21895830, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32904144).

21895830 is an abundant number, since it is smaller than the sum of its proper divisors (43912458).

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

21895830 is a wasteful number, since it uses less digits than its factorization.

21895830 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1342 (or 1339 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The square root of 21895830 is about 4679.2980242767. The cubic root of 21895830 is about 279.7609779897.

The spelling of 21895830 in words is "twenty-one million, eight hundred ninety-five thousand, eight hundred thirty".