21929722 has 4 divisors (see below), whose sum is σ = 32894586. Its totient is φ = 10964860.

The previous prime is 21929717. The next prime is 21929723. The reversal of 21929722 is 22792912.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 21353641 + 576081 = 4621^2 + 759^2 .

It is not an unprimeable number, because it can be changed into a prime (21929723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5482429 + ... + 5482432.

Almost surely, 2^21929722 is an apocalyptic number.

21929722 is a deficient number, since it is larger than the sum of its proper divisors (10964864).

21929722 is a wasteful number, since it uses less digits than its factorization.

21929722 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10964863.

The product of its digits is 9072, while the sum is 34.

The square root of 21929722 is about 4682.9181073344. The cubic root of 21929722 is about 279.9052485522.

The spelling of 21929722 in words is "twenty-one million, nine hundred twenty-nine thousand, seven hundred twenty-two".