21173259 has 8 divisors (see below), whose sum is σ = 28337040. Its totient is φ = 14062496.

The previous prime is 21173233. The next prime is 21173263. The reversal of 21173259 is 95237112.

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

It is a cyclic number.

It is not a de Polignac number, because 21173259 - 2¹⁷ = 21042187 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21153259) 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, 12312 + ... + 13925.

It is an arithmetic number, because the mean of its divisors is an integer number (3542130).

Almost surely, 2^21173259 is an apocalyptic number.

21173259 is a deficient number, since it is larger than the sum of its proper divisors (7163781).

21173259 is a wasteful number, since it uses less digits than its factorization.

21173259 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26509.

The product of its digits is 3780, while the sum is 30.

The square root of 21173259 is about 4601.4409699571. The cubic root of 21173259 is about 276.6490840587.

The spelling of 21173259 in words is "twenty-one million, one hundred seventy-three thousand, two hundred fifty-nine".