21922281 has 6 divisors (see below), whose sum is σ = 31665530. Its totient is φ = 14614848.

The previous prime is 21922279. The next prime is 21922319. The reversal of 21922281 is 18222912.

It can be written as a sum of positive squares in only one way, i.e., 21902400 + 19881 = 4680^2 + 141^2 .

It is not a de Polignac number, because 21922281 - 2¹ = 21922279 is a prime.

It is a super-2 number, since 2×21922281² = 961172808485922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21922261) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1217896 + ... + 1217913.

Almost surely, 2^21922281 is an apocalyptic number.

It is an amenable number.

21922281 is a deficient number, since it is larger than the sum of its proper divisors (9743249).

21922281 is a wasteful number, since it uses less digits than its factorization.

21922281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2435815 (or 2435812 counting only the distinct ones).

The product of its digits is 1152, while the sum is 27.

The square root of 21922281 is about 4682.1235566781. The cubic root of 21922281 is about 279.8735866434.

It can be divided in two parts, 219 and 22281, that added together give a square (22500 = 150²).

The spelling of 21922281 in words is "twenty-one million, nine hundred twenty-two thousand, two hundred eighty-one".