21021323 has 2 divisors, whose sum is σ = 21021324. Its totient is φ = 21021322.

The previous prime is 21021293. The next prime is 21021331. The reversal of 21021323 is 32312012.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21021323 - 2⁸ = 21021067 is a prime.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 21021298 and 21021307.

It is not a weakly prime, because it can be changed into another prime (21021383) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510661 + 10510662.

It is an arithmetic number, because the mean of its divisors is an integer number (10510662).

Almost surely, 2^21021323 is an apocalyptic number.

21021323 is a deficient number, since it is larger than the sum of its proper divisors (1).

21021323 is an equidigital number, since it uses as much as digits as its factorization.

21021323 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 21021323 is about 4584.9016347137. The cubic root of 21021323 is about 275.9857646862.

Adding to 21021323 its reverse (32312012), we get a palindrome (53333335).

The spelling of 21021323 in words is "twenty-one million, twenty-one thousand, three hundred twenty-three".