21895812 has 48 divisors (see below), whose sum is σ = 58732800. Its totient is φ = 7045920.

The previous prime is 21895807. The next prime is 21895829. The reversal of 21895812 is 21859812.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 364 + ... + 6627.

It is an arithmetic number, because the mean of its divisors is an integer number (1223600).

Almost surely, 2^21895812 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 21895812, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29366400).

21895812 is an abundant number, since it is smaller than the sum of its proper divisors (36836988).

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

21895812 is a wasteful number, since it uses less digits than its factorization.

21895812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7033 (or 7025 counting only the distinct ones).

The product of its digits is 11520, while the sum is 36.

The square root of 21895812 is about 4679.2961009109. The cubic root of 21895812 is about 279.7609013282.

It can be divided in two parts, 2189 and 5812, that added together give a triangular number (8001 = T₁₂₆).

The spelling of 21895812 in words is "twenty-one million, eight hundred ninety-five thousand, eight hundred twelve".