21347233 has 2 divisors, whose sum is σ = 21347234. Its totient is φ = 21347232.

The previous prime is 21347213. The next prime is 21347239. The reversal of 21347233 is 33274312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21233664 + 113569 = 4608^2 + 337^2 .

It is a cyclic number.

It is not a de Polignac number, because 21347233 - 2⁵ = 21347201 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21347198 and 21347207.

It is not a weakly prime, because it can be changed into another prime (21347239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10673616 + 10673617.

It is an arithmetic number, because the mean of its divisors is an integer number (10673617).

Almost surely, 2^21347233 is an apocalyptic number.

It is an amenable number.

21347233 is a deficient number, since it is larger than the sum of its proper divisors (1).

21347233 is an equidigital number, since it uses as much as digits as its factorization.

21347233 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3024, while the sum is 25.

The square root of 21347233 is about 4620.3065915586. The cubic root of 21347233 is about 277.4047309794.

The spelling of 21347233 in words is "twenty-one million, three hundred forty-seven thousand, two hundred thirty-three".