20311111217 has 2 divisors, whose sum is σ = 20311111218. Its totient is φ = 20311111216.

The previous prime is 20311111157. The next prime is 20311111243. The reversal of 20311111217 is 71211111302.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13959658801 + 6351452416 = 118151^2 + 79696^2 .

It is a cyclic number.

It is not a de Polignac number, because 20311111217 - 2⁶ = 20311111153 is a prime.

It is not a weakly prime, because it can be changed into another prime (20311111277) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10155555608 + 10155555609.

It is an arithmetic number, because the mean of its divisors is an integer number (10155555609).

Almost surely, 2^20311111217 is an apocalyptic number.

It is an amenable number.

20311111217 is a deficient number, since it is larger than the sum of its proper divisors (1).

20311111217 is an equidigital number, since it uses as much as digits as its factorization.

20311111217 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 84, while the sum is 20.

Adding to 20311111217 its reverse (71211111302), we get a palindrome (91522222519).

The spelling of 20311111217 in words is "twenty billion, three hundred eleven million, one hundred eleven thousand, two hundred seventeen".