21738851 has 12 divisors (see below), whose sum is σ = 22674960. Its totient is φ = 20835360.

The previous prime is 21738839. The next prime is 21738853. The reversal of 21738851 is 15883712.

It is not a de Polignac number, because 21738851 - 2¹⁰ = 21737827 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21738853) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 199385 + ... + 199493.

It is an arithmetic number, because the mean of its divisors is an integer number (1889580).

Almost surely, 2^21738851 is an apocalyptic number.

21738851 is a deficient number, since it is larger than the sum of its proper divisors (936109).

21738851 is an equidigital number, since it uses as much as digits as its factorization.

21738851 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 286 (or 233 counting only the distinct ones).

The product of its digits is 13440, while the sum is 35.

The square root of 21738851 is about 4662.4940750633. The cubic root of 21738851 is about 279.0908051785.

The spelling of 21738851 in words is "twenty-one million, seven hundred thirty-eight thousand, eight hundred fifty-one".