20321111231 has 4 divisors (see below), whose sum is σ = 20654244264. Its totient is φ = 19987978200.

The previous prime is 20321111203. The next prime is 20321111281. The reversal of 20321111231 is 13211112302.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13211112302 = 2 ⋅6605556151.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20321111231 is a prime.

It is a super-2 number, since 2×20321111231² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20321111281) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 166566425 + ... + 166566546.

It is an arithmetic number, because the mean of its divisors is an integer number (5163561066).

Almost surely, 2^20321111231 is an apocalyptic number.

20321111231 is a deficient number, since it is larger than the sum of its proper divisors (333133033).

20321111231 is an equidigital number, since it uses as much as digits as its factorization.

20321111231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 333133032.

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 20321111231 its reverse (13211112302), we get a palindrome (33532223533).

The spelling of 20321111231 in words is "twenty billion, three hundred twenty-one million, one hundred eleven thousand, two hundred thirty-one".