21888331 has 2 divisors, whose sum is σ = 21888332. Its totient is φ = 21888330.

The previous prime is 21888313. The next prime is 21888379. The reversal of 21888331 is 13388812.

Together with previous prime (21888313) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21888331 - 2¹¹ = 21886283 is a prime.

It is a super-2 number, since 2×21888331² = 958198067931122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21888131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10944165 + 10944166.

It is an arithmetic number, because the mean of its divisors is an integer number (10944166).

Almost surely, 2^21888331 is an apocalyptic number.

21888331 is a deficient number, since it is larger than the sum of its proper divisors (1).

21888331 is an equidigital number, since it uses as much as digits as its factorization.

21888331 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9216, while the sum is 34.

The square root of 21888331 is about 4678.4966602532. The cubic root of 21888331 is about 279.7290363350.

The spelling of 21888331 in words is "twenty-one million, eight hundred eighty-eight thousand, three hundred thirty-one".