31111545581 has 2 divisors, whose sum is σ = 31111545582. Its totient is φ = 31111545580.

The previous prime is 31111545547. The next prime is 31111545587. The reversal of 31111545581 is 18554511113.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 29949417481 + 1162128100 = 173059^2 + 34090^2 .

It is a cyclic number.

It is not a de Polignac number, because 31111545581 - 2¹⁰ = 31111544557 is a prime.

It is a super-3 number, since 3×31111545581³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31111545587) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15555772790 + 15555772791.

It is an arithmetic number, because the mean of its divisors is an integer number (15555772791).

Almost surely, 2^31111545581 is an apocalyptic number.

It is an amenable number.

31111545581 is a deficient number, since it is larger than the sum of its proper divisors (1).

31111545581 is an equidigital number, since it uses as much as digits as its factorization.

31111545581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12000, while the sum is 35.

The spelling of 31111545581 in words is "thirty-one billion, one hundred eleven million, five hundred forty-five thousand, five hundred eighty-one".