21938727 has 4 divisors (see below), whose sum is σ = 29251640. Its totient is φ = 14625816.

The previous prime is 21938723. The next prime is 21938747. The reversal of 21938727 is 72783912.

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

It is not a de Polignac number, because 21938727 - 2² = 21938723 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21938723) 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, 3656452 + ... + 3656457.

It is an arithmetic number, because the mean of its divisors is an integer number (7312910).

Almost surely, 2^21938727 is an apocalyptic number.

21938727 is a deficient number, since it is larger than the sum of its proper divisors (7312913).

21938727 is an equidigital number, since it uses as much as digits as its factorization.

21938727 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7312912.

The product of its digits is 42336, while the sum is 39.

The square root of 21938727 is about 4683.8794817971. The cubic root of 21938727 is about 279.9435557993.

The spelling of 21938727 in words is "twenty-one million, nine hundred thirty-eight thousand, seven hundred twenty-seven".