81369161 has 2 divisors, whose sum is σ = 81369162. Its totient is φ = 81369160.

The previous prime is 81369149. The next prime is 81369199. The reversal of 81369161 is 16196318.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 77088400 + 4280761 = 8780^2 + 2069^2 .

It is a cyclic number.

It is not a de Polignac number, because 81369161 - 2⁶ = 81369097 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81369121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40684580 + 40684581.

It is an arithmetic number, because the mean of its divisors is an integer number (40684581).

Almost surely, 2^81369161 is an apocalyptic number.

It is an amenable number.

81369161 is a deficient number, since it is larger than the sum of its proper divisors (1).

81369161 is an equidigital number, since it uses as much as digits as its factorization.

81369161 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7776, while the sum is 35.

The square root of 81369161 is about 9020.4856299425. The cubic root of 81369161 is about 433.3311865114.

The spelling of 81369161 in words is "eighty-one million, three hundred sixty-nine thousand, one hundred sixty-one".