20311100021 has 2 divisors, whose sum is σ = 20311100022. Its totient is φ = 20311100020.

The previous prime is 20311099973. The next prime is 20311100039. The reversal of 20311100021 is 12000111302.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19428178225 + 882921796 = 139385^2 + 29714^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20311100021 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20311099975 and 20311100011.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20311100041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10155550010 + 10155550011.

It is an arithmetic number, because the mean of its divisors is an integer number (10155550011).

Almost surely, 2^20311100021 is an apocalyptic number.

It is an amenable number.

20311100021 is a deficient number, since it is larger than the sum of its proper divisors (1).

20311100021 is an equidigital number, since it uses as much as digits as its factorization.

20311100021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12, while the sum is 11.

Adding to 20311100021 its reverse (12000111302), we get a palindrome (32311211323).

The spelling of 20311100021 in words is "twenty billion, three hundred eleven million, one hundred thousand, twenty-one".