20311320181 has 2 divisors, whose sum is σ = 20311320182. Its totient is φ = 20311320180.

The previous prime is 20311320167. The next prime is 20311320269. The reversal of 20311320181 is 18102311302.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20042064900 + 269255281 = 141570^2 + 16409^2 .

It is a cyclic number.

It is not a de Polignac number, because 20311320181 - 2¹³ = 20311311989 is a prime.

It is a super-2 number, since 2×20311320181² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20311320151) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10155660090 + 10155660091.

It is an arithmetic number, because the mean of its divisors is an integer number (10155660091).

Almost surely, 2^20311320181 is an apocalyptic number.

It is an amenable number.

20311320181 is a deficient number, since it is larger than the sum of its proper divisors (1).

20311320181 is an equidigital number, since it uses as much as digits as its factorization.

20311320181 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 22.

Adding to 20311320181 its reverse (18102311302), we get a palindrome (38413631483).

The spelling of 20311320181 in words is "twenty billion, three hundred eleven million, three hundred twenty thousand, one hundred eighty-one".