21988267 has 8 divisors (see below), whose sum is σ = 25170912. Its totient is φ = 18816000.

The previous prime is 21988247. The next prime is 21988279. The reversal of 21988267 is 76288912.

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

It is not a de Polignac number, because 21988267 - 2⁷ = 21988139 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21988237) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2667 + ... + 7147.

It is an arithmetic number, because the mean of its divisors is an integer number (3146364).

Almost surely, 2^21988267 is an apocalyptic number.

21988267 is a deficient number, since it is larger than the sum of its proper divisors (3182645).

21988267 is an equidigital number, since it uses as much as digits as its factorization.

21988267 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5189.

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

The square root of 21988267 is about 4689.1648510156. The cubic root of 21988267 is about 280.1541115902.

The spelling of 21988267 in words is "twenty-one million, nine hundred eighty-eight thousand, two hundred sixty-seven".