291818086981 has 2 divisors, whose sum is σ = 291818086982. Its totient is φ = 291818086980.

The previous prime is 291818086969. The next prime is 291818087009. The reversal of 291818086981 is 189680818192.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 280220950881 + 11597136100 = 529359^2 + 107690^2 .

It is a cyclic number.

It is not a de Polignac number, because 291818086981 - 2¹³ = 291818078789 is a prime.

It is a super-2 number, since 2×291818086981² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (291818086921) 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, 145909043490 + 145909043491.

It is an arithmetic number, because the mean of its divisors is an integer number (145909043491).

Almost surely, 2^291818086981 is an apocalyptic number.

It is an amenable number.

291818086981 is a deficient number, since it is larger than the sum of its proper divisors (1).

291818086981 is an equidigital number, since it uses as much as digits as its factorization.

291818086981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3981312, while the sum is 61.

The spelling of 291818086981 in words is "two hundred ninety-one billion, eight hundred eighteen million, eighty-six thousand, nine hundred eighty-one".