21929168 has 10 divisors (see below), whose sum is σ = 42487794. Its totient is φ = 10964576.

The previous prime is 21929153. The next prime is 21929177. The reversal of 21929168 is 86192912.

It can be written as a sum of positive squares in only one way, i.e., 16875664 + 5053504 = 4108^2 + 2248^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 685271 + ... + 685302.

Almost surely, 2^21929168 is an apocalyptic number.

It is an amenable number.

21929168 is a deficient number, since it is larger than the sum of its proper divisors (20558626).

21929168 is a wasteful number, since it uses less digits than its factorization.

21929168 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1370581 (or 1370575 counting only the distinct ones).

The product of its digits is 15552, while the sum is 38.

The square root of 21929168 is about 4682.8589558089. The cubic root of 21929168 is about 279.9028914952.

The spelling of 21929168 in words is "twenty-one million, nine hundred twenty-nine thousand, one hundred sixty-eight".