21671259 has 12 divisors (see below), whose sum is σ = 29328168. Its totient is φ = 14234080.

The previous prime is 21671257. The next prime is 21671261. The reversal of 21671259 is 95217612.

It is an interprime number because it is at equal distance from previous prime (21671257) and next prime (21671261).

It is not a de Polignac number, because 21671259 - 2¹ = 21671257 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21671257) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 14407 + ... + 15839.

It is an arithmetic number, because the mean of its divisors is an integer number (2444014).

Almost surely, 2^21671259 is an apocalyptic number.

21671259 is a deficient number, since it is larger than the sum of its proper divisors (7656909).

21671259 is an equidigital number, since it uses as much as digits as its factorization.

21671259 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1578 (or 1507 counting only the distinct ones).

The product of its digits is 7560, while the sum is 33.

The square root of 21671259 is about 4655.2399508511. The cubic root of 21671259 is about 278.8012484617.

The spelling of 21671259 in words is "twenty-one million, six hundred seventy-one thousand, two hundred fifty-nine".