21329279 has 8 divisors (see below), whose sum is σ = 21997440. Its totient is φ = 20666016.

The previous prime is 21329263. The next prime is 21329299. The reversal of 21329279 is 97292312.

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 21329279 - 2⁴ = 21329263 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21329299) 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, 8882 + ... + 11024.

It is an arithmetic number, because the mean of its divisors is an integer number (2749680).

Almost surely, 2^21329279 is an apocalyptic number.

21329279 is a deficient number, since it is larger than the sum of its proper divisors (668161).

21329279 is a wasteful number, since it uses less digits than its factorization.

21329279 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2449.

The product of its digits is 13608, while the sum is 35.

The square root of 21329279 is about 4618.3632382046. The cubic root of 21329279 is about 277.3269391413.

It can be divided in two parts, 2132 and 9279, that added together give a palindrome (11411).

The spelling of 21329279 in words is "twenty-one million, three hundred twenty-nine thousand, two hundred seventy-nine".