21309083 has 4 divisors (see below), whose sum is σ = 21360360. Its totient is φ = 21257808.

The previous prime is 21309061. The next prime is 21309103. The reversal of 21309083 is 38090312.

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

It is a cyclic number.

It is not a de Polignac number, because 21309083 - 2⁶ = 21309019 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21309023) 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, 25010 + ... + 25847.

It is an arithmetic number, because the mean of its divisors is an integer number (5340090).

Almost surely, 2^21309083 is an apocalyptic number.

21309083 is a deficient number, since it is larger than the sum of its proper divisors (51277).

21309083 is an equidigital number, since it uses as much as digits as its factorization.

21309083 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51276.

The product of its (nonzero) digits is 1296, while the sum is 26.

The square root of 21309083 is about 4616.1762314712. The cubic root of 21309083 is about 277.2393808830.

Adding to 21309083 its reverse (38090312), we get a palindrome (59399395).

The spelling of 21309083 in words is "twenty-one million, three hundred nine thousand, eighty-three".