20312210021 has 4 divisors (see below), whose sum is σ = 20312615232. Its totient is φ = 20311804812.

The previous prime is 20312209999. The next prime is 20312210063. The reversal of 20312210021 is 12001221302.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20312210021 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 20312209978 and 20312210005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20312210081) 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, 114701 + ... + 231906.

It is an arithmetic number, because the mean of its divisors is an integer number (5078153808).

Almost surely, 2^20312210021 is an apocalyptic number.

It is an amenable number.

20312210021 is a deficient number, since it is larger than the sum of its proper divisors (405211).

20312210021 is an equidigital number, since it uses as much as digits as its factorization.

20312210021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 405210.

The product of its (nonzero) digits is 48, while the sum is 14.

Adding to 20312210021 its reverse (12001221302), we get a palindrome (32313431323).

The spelling of 20312210021 in words is "twenty billion, three hundred twelve million, two hundred ten thousand, twenty-one".