21978022 has 16 divisors (see below), whose sum is σ = 37857600. Its totient is φ = 9464040.

The previous prime is 21978017. The next prime is 21978023. The reversal of 21978022 is 22087912.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21978023) 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, 25872 + ... + 26707.

It is an arithmetic number, because the mean of its divisors is an integer number (2366100).

Almost surely, 2^21978022 is an apocalyptic number.

21978022 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21978022 is a deficient number, since it is larger than the sum of its proper divisors (15879578).

21978022 is a wasteful number, since it uses less digits than its factorization.

21978022 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52611.

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 21978022 is about 4688.0723117290. The cubic root of 21978022 is about 280.1105940670.

The spelling of 21978022 in words is "twenty-one million, nine hundred seventy-eight thousand, twenty-two".