21929788 has 6 divisors (see below), whose sum is σ = 38377136. Its totient is φ = 10964892.

The previous prime is 21929783. The next prime is 21929801. The reversal of 21929788 is 88792912.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21929783) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2741220 + ... + 2741227.

Almost surely, 2^21929788 is an apocalyptic number.

It is an amenable number.

21929788 is a deficient number, since it is larger than the sum of its proper divisors (16447348).

21929788 is a wasteful number, since it uses less digits than its factorization.

21929788 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5482451 (or 5482449 counting only the distinct ones).

The product of its digits is 145152, while the sum is 46.

The square root of 21929788 is about 4682.9251542172. The cubic root of 21929788 is about 279.9055293541.

The spelling of 21929788 in words is "twenty-one million, nine hundred twenty-nine thousand, seven hundred eighty-eight".