21840022 has 8 divisors (see below), whose sum is σ = 32901336. Its totient is φ = 10872912.

The previous prime is 21839989. The next prime is 21840023. The reversal of 21840022 is 22004812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21840023) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22968 + ... + 23899.

It is an arithmetic number, because the mean of its divisors is an integer number (4112667).

Almost surely, 2^21840022 is an apocalyptic number.

21840022 is a deficient number, since it is larger than the sum of its proper divisors (11061314).

21840022 is a wasteful number, since it uses less digits than its factorization.

21840022 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47102.

The product of its (nonzero) digits is 256, while the sum is 19.

The square root of 21840022 is about 4673.3309320013. The cubic root of 21840022 is about 279.5230912296.

Adding to 21840022 its reverse (22004812), we get a palindrome (43844834).

The spelling of 21840022 in words is "twenty-one million, eight hundred forty thousand, twenty-two".