21311323 has 8 divisors (see below), whose sum is σ = 23316480. Its totient is φ = 19317480.

The previous prime is 21311261. The next prime is 21311347. The reversal of 21311323 is 32311312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21311323 - 2¹³ = 21303131 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21311297 and 21311306.

It is not an unprimeable number, because it can be changed into a prime (21311393) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1398 + ... + 6676.

It is an arithmetic number, because the mean of its divisors is an integer number (2914560).

Almost surely, 2^21311323 is an apocalyptic number.

21311323 is a deficient number, since it is larger than the sum of its proper divisors (2005157).

21311323 is a wasteful number, since it uses less digits than its factorization.

21311323 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5657.

The product of its digits is 108, while the sum is 16.

The square root of 21311323 is about 4616.4188501478. The cubic root of 21311323 is about 277.2490949637.

Adding to 21311323 its reverse (32311312), we get a palindrome (53622635).

The spelling of 21311323 in words is "twenty-one million, three hundred eleven thousand, three hundred twenty-three".