20211131081 has 2 divisors, whose sum is σ = 20211131082. Its totient is φ = 20211131080.

The previous prime is 20211131077. The next prime is 20211131107. The reversal of 20211131081 is 18013111202.

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., 19235193481 + 975937600 = 138691^2 + 31240^2 .

It is a cyclic number.

It is not a de Polignac number, because 20211131081 - 2² = 20211131077 is a prime.

It is a super-2 number, since 2×20211131081² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20211131011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10105565540 + 10105565541.

It is an arithmetic number, because the mean of its divisors is an integer number (10105565541).

Almost surely, 2^20211131081 is an apocalyptic number.

It is an amenable number.

20211131081 is a deficient number, since it is larger than the sum of its proper divisors (1).

20211131081 is an equidigital number, since it uses as much as digits as its factorization.

20211131081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 96, while the sum is 20.

Adding to 20211131081 its reverse (18013111202), we get a palindrome (38224242283).

The spelling of 20211131081 in words is "twenty billion, two hundred eleven million, one hundred thirty-one thousand, eighty-one".