21838406 has 8 divisors (see below), whose sum is σ = 32779560. Its totient is φ = 10911888.

The previous prime is 21838381. The next prime is 21838433. The reversal of 21838406 is 60483812.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1565 + ... + 6791.

It is an arithmetic number, because the mean of its divisors is an integer number (4097445).

Almost surely, 2^21838406 is an apocalyptic number.

21838406 is a deficient number, since it is larger than the sum of its proper divisors (10941154).

21838406 is a wasteful number, since it uses less digits than its factorization.

21838406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7318.

The product of its (nonzero) digits is 9216, while the sum is 32.

The square root of 21838406 is about 4673.1580328510. The cubic root of 21838406 is about 279.5161968462.

The spelling of 21838406 in words is "twenty-one million, eight hundred thirty-eight thousand, four hundred six".