20311012021 has 4 divisors (see below), whose sum is σ = 21505777452. Its totient is φ = 19116246592.

The previous prime is 20311012009. The next prime is 20311012037. The reversal of 20311012021 is 12021011302.

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

It can be written as a sum of positive squares in 2 ways, for example, as 17612209521 + 2698802500 = 132711^2 + 51950^2 .

It is a cyclic number.

It is not a de Polignac number, because 20311012021 - 2¹⁹ = 20310487733 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20311011992 and 20311012010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20311012061) 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, 597382690 + ... + 597382723.

It is an arithmetic number, because the mean of its divisors is an integer number (5376444363).

Almost surely, 2^20311012021 is an apocalyptic number.

It is an amenable number.

20311012021 is a deficient number, since it is larger than the sum of its proper divisors (1194765431).

20311012021 is a wasteful number, since it uses less digits than its factorization.

20311012021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1194765430.

The product of its (nonzero) digits is 24, while the sum is 13.

Adding to 20311012021 its reverse (12021011302), we get a palindrome (32332023323).

The spelling of 20311012021 in words is "twenty billion, three hundred eleven million, twelve thousand, twenty-one".