21051323 has 2 divisors, whose sum is σ = 21051324. Its totient is φ = 21051322.

The previous prime is 21051311. The next prime is 21051337. The reversal of 21051323 is 32315012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21051323 - 2¹⁸ = 20789179 is a prime.

It is not a weakly prime, because it can be changed into another prime (21051343) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10525661 + 10525662.

It is an arithmetic number, because the mean of its divisors is an integer number (10525662).

Almost surely, 2^21051323 is an apocalyptic number.

21051323 is a deficient number, since it is larger than the sum of its proper divisors (1).

21051323 is an equidigital number, since it uses as much as digits as its factorization.

21051323 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 180, while the sum is 17.

The square root of 21051323 is about 4588.1720761105. The cubic root of 21051323 is about 276.1169907657.

Adding to 21051323 its reverse (32315012), we get a palindrome (53366335).

The spelling of 21051323 in words is "twenty-one million, fifty-one thousand, three hundred twenty-three".