21838705 has 8 divisors (see below), whose sum is σ = 29950272. Its totient is φ = 14975088.

The previous prime is 21838679. The next prime is 21838723. The reversal of 21838705 is 50783812.

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

It is a cyclic number.

It is not a de Polignac number, because 21838705 - 2¹⁹ = 21314417 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 311947 + ... + 312016.

It is an arithmetic number, because the mean of its divisors is an integer number (3743784).

Almost surely, 2^21838705 is an apocalyptic number.

It is an amenable number.

21838705 is a deficient number, since it is larger than the sum of its proper divisors (8111567).

21838705 is an equidigital number, since it uses as much as digits as its factorization.

21838705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 623975.

The product of its (nonzero) digits is 13440, while the sum is 34.

The square root of 21838705 is about 4673.1900239558. The cubic root of 21838705 is about 279.5174725034.

The spelling of 21838705 in words is "twenty-one million, eight hundred thirty-eight thousand, seven hundred five".