20123021231 has 4 divisors (see below), whose sum is σ = 20159809752. Its totient is φ = 20086232712.

The previous prime is 20123021213. The next prime is 20123021299. The reversal of 20123021231 is 13212032102.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20123021231 is a prime.

It is a super-2 number, since 2×20123021231² (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 (20123021531) 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, 18393440 + ... + 18394533.

It is an arithmetic number, because the mean of its divisors is an integer number (5039952438).

Almost surely, 2^20123021231 is an apocalyptic number.

20123021231 is a deficient number, since it is larger than the sum of its proper divisors (36788521).

20123021231 is an equidigital number, since it uses as much as digits as its factorization.

20123021231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36788520.

The product of its (nonzero) digits is 144, while the sum is 17.

Adding to 20123021231 its reverse (13212032102), we get a palindrome (33335053333).

The spelling of 20123021231 in words is "twenty billion, one hundred twenty-three million, twenty-one thousand, two hundred thirty-one".