21929438 has 8 divisors (see below), whose sum is σ = 33091632. Its totient is φ = 10898896.

The previous prime is 21929437. The next prime is 21929443. The reversal of 21929438 is 83492912.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21929437) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32495 + ... + 33162.

It is an arithmetic number, because the mean of its divisors is an integer number (4136454).

Almost surely, 2^21929438 is an apocalyptic number.

21929438 is a deficient number, since it is larger than the sum of its proper divisors (11162194).

21929438 is a wasteful number, since it uses less digits than its factorization.

21929438 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65826.

The product of its digits is 31104, while the sum is 38.

The square root of 21929438 is about 4682.8877842630. The cubic root of 21929438 is about 279.9040402463.

The spelling of 21929438 in words is "twenty-one million, nine hundred twenty-nine thousand, four hundred thirty-eight".