21974229 has 6 divisors (see below), whose sum is σ = 31740566. Its totient is φ = 14649480.

The previous prime is 21974201. The next prime is 21974243. The reversal of 21974229 is 92247912.

It can be written as a sum of positive squares in only one way, i.e., 11573604 + 10400625 = 3402^2 + 3225^2 .

It is not a de Polignac number, because 21974229 - 2¹⁵ = 21941461 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21974193 and 21974202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21974299) 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, 1220782 + ... + 1220799.

Almost surely, 2^21974229 is an apocalyptic number.

It is an amenable number.

21974229 is a deficient number, since it is larger than the sum of its proper divisors (9766337).

21974229 is a wasteful number, since it uses less digits than its factorization.

21974229 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2441587 (or 2441584 counting only the distinct ones).

The product of its digits is 18144, while the sum is 36.

The square root of 21974229 is about 4687.6677569981. The cubic root of 21974229 is about 280.0944791711.

The spelling of 21974229 in words is "twenty-one million, nine hundred seventy-four thousand, two hundred twenty-nine".