21321822 has 16 divisors (see below), whose sum is σ = 42970752. Its totient is φ = 7052760.

The previous prime is 21321821. The next prime is 21321829. The reversal of 21321822 is 22812312.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21321821) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12778 + ... + 14349.

It is an arithmetic number, because the mean of its divisors is an integer number (2685672).

Almost surely, 2^21321822 is an apocalyptic number.

21321822 is an abundant number, since it is smaller than the sum of its proper divisors (21648930).

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

21321822 is a wasteful number, since it uses less digits than its factorization.

21321822 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27263.

The product of its digits is 384, while the sum is 21.

The square root of 21321822 is about 4617.5558469823. Note that the first 3 decimals coincide. The cubic root of 21321822 is about 277.2946163104.

The spelling of 21321822 in words is "twenty-one million, three hundred twenty-one thousand, eight hundred twenty-two".