20313121021 has 8 divisors (see below), whose sum is σ = 21025920600. Its totient is φ = 19601144640.

The previous prime is 20313121013. The next prime is 20313121051. The reversal of 20313121021 is 12012131302.

It can be written as a sum of positive squares in 4 ways, for example, as 67815225 + 20245305796 = 8235^2 + 142286^2 .

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 20313121021 - 2³ = 20313121013 is a prime.

It is a super-2 number, since 2×20313121021² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20313120986 and 20313121004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20313121051) 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, 155370 + ... + 254491.

It is an arithmetic number, because the mean of its divisors is an integer number (2628240075).

Almost surely, 2^20313121021 is an apocalyptic number.

It is an amenable number.

20313121021 is a deficient number, since it is larger than the sum of its proper divisors (712799579).

20313121021 is a wasteful number, since it uses less digits than its factorization.

20313121021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 411599.

The product of its (nonzero) digits is 72, while the sum is 16.

Adding to 20313121021 its reverse (12012131302), we get a palindrome (32325252323).

The spelling of 20313121021 in words is "twenty billion, three hundred thirteen million, one hundred twenty-one thousand, twenty-one".