21031323 has 16 divisors (see below), whose sum is σ = 28563840. Its totient is φ = 13762496.

The previous prime is 21031313. The next prime is 21031333. The reversal of 21031323 is 32313012.

It is an interprime number because it is at equal distance from previous prime (21031313) and next prime (21031333).

It is a cyclic number.

It is not a de Polignac number, because 21031323 - 2⁵ = 21031291 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21031303) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 60436 + ... + 60782.

It is an arithmetic number, because the mean of its divisors is an integer number (1785240).

Almost surely, 2^21031323 is an apocalyptic number.

21031323 is a deficient number, since it is larger than the sum of its proper divisors (7532517).

21031323 is a wasteful number, since it uses less digits than its factorization.

21031323 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 666.

The product of its (nonzero) digits is 108, while the sum is 15.

The square root of 21031323 is about 4585.9920409874. The cubic root of 21031323 is about 276.0295205769.

Adding to 21031323 its reverse (32313012), we get a palindrome (53344335).

The spelling of 21031323 in words is "twenty-one million, thirty-one thousand, three hundred twenty-three".