21869827 has 6 divisors (see below), whose sum is σ = 25440468. Its totient is φ = 18745524.

The previous prime is 21869821. The next prime is 21869839. The reversal of 21869827 is 72896812.

It is not a de Polignac number, because 21869827 - 2⁷ = 21869699 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21869821) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 223113 + ... + 223210.

It is an arithmetic number, because the mean of its divisors is an integer number (4240078).

Almost surely, 2^21869827 is an apocalyptic number.

21869827 is a deficient number, since it is larger than the sum of its proper divisors (3570641).

21869827 is an equidigital number, since it uses as much as digits as its factorization.

21869827 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 446337 (or 446330 counting only the distinct ones).

The product of its digits is 96768, while the sum is 43.

The square root of 21869827 is about 4676.5186838074. The cubic root of 21869827 is about 279.6501881523.

The spelling of 21869827 in words is "twenty-one million, eight hundred sixty-nine thousand, eight hundred twenty-seven".