21320329 has 4 divisors (see below), whose sum is σ = 22574484. Its totient is φ = 20066176.

The previous prime is 21320323. The next prime is 21320401. The reversal of 21320329 is 92302312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8732025 + 12588304 = 2955^2 + 3548^2 .

It is a cyclic number.

It is not a de Polignac number, because 21320329 - 2⁵ = 21320297 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21320323) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 627052 + ... + 627085.

It is an arithmetic number, because the mean of its divisors is an integer number (5643621).

Almost surely, 2^21320329 is an apocalyptic number.

It is an amenable number.

21320329 is a deficient number, since it is larger than the sum of its proper divisors (1254155).

21320329 is a wasteful number, since it uses less digits than its factorization.

21320329 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1254154.

The product of its (nonzero) digits is 648, while the sum is 22.

The square root of 21320329 is about 4617.3941785384. The cubic root of 21320329 is about 277.2881439035.

The spelling of 21320329 in words is "twenty-one million, three hundred twenty thousand, three hundred twenty-nine".