20311221001081 has 2 divisors, whose sum is σ = 20311221001082. Its totient is φ = 20311221001080.

The previous prime is 20311221001069. The next prime is 20311221001111. The reversal of 20311221001081 is 18010012211302.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15127899091600 + 5183321909481 = 3889460^2 + 2276691^2 .

It is a cyclic number.

It is not a de Polignac number, because 20311221001081 - 2¹¹ = 20311220999033 is a prime.

It is a super-2 number, since 2×20311221001081² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20311221001021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10155610500540 + 10155610500541.

It is an arithmetic number, because the mean of its divisors is an integer number (10155610500541).

Almost surely, 2^{20311221001081} is an apocalyptic number.

It is an amenable number.

20311221001081 is a deficient number, since it is larger than the sum of its proper divisors (1).

20311221001081 is an equidigital number, since it uses as much as digits as its factorization.

20311221001081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 192, while the sum is 22.

Adding to 20311221001081 its reverse (18010012211302), we get a palindrome (38321233212383).

The spelling of 20311221001081 in words is "twenty trillion, three hundred eleven billion, two hundred twenty-one million, one thousand, eighty-one".