21891159 has 6 divisors (see below), whose sum is σ = 31620576. Its totient is φ = 14594100.

The previous prime is 21891157. The next prime is 21891169. The reversal of 21891159 is 95119812.

It is not a de Polignac number, because 21891159 - 2¹ = 21891157 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21891157) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1216167 + ... + 1216184.

It is an arithmetic number, because the mean of its divisors is an integer number (5270096).

Almost surely, 2^21891159 is an apocalyptic number.

21891159 is a deficient number, since it is larger than the sum of its proper divisors (9729417).

21891159 is a wasteful number, since it uses less digits than its factorization.

21891159 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2432357 (or 2432354 counting only the distinct ones).

The product of its digits is 6480, while the sum is 36.

The square root of 21891159 is about 4678.7988843292. The cubic root of 21891159 is about 279.7410829311.

The spelling of 21891159 in words is "twenty-one million, eight hundred ninety-one thousand, one hundred fifty-nine".