21922978 has 16 divisors (see below), whose sum is σ = 40999104. Its totient is φ = 8541360.

The previous prime is 21922969. The next prime is 21922993. The reversal of 21922978 is 87922912.

It is a self number, because there is not a number n which added to its sum of digits gives 21922978.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 71025 + ... + 71332.

It is an arithmetic number, because the mean of its divisors is an integer number (2562444).

Almost surely, 2^21922978 is an apocalyptic number.

21922978 is a deficient number, since it is larger than the sum of its proper divisors (19076126).

21922978 is a wasteful number, since it uses less digits than its factorization.

21922978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 142377.

The product of its digits is 36288, while the sum is 40.

The square root of 21922978 is about 4682.1979881248. The cubic root of 21922978 is about 279.8765527250.

The spelling of 21922978 in words is "twenty-one million, nine hundred twenty-two thousand, nine hundred seventy-eight".