81166469 has 2 divisors, whose sum is σ = 81166470. Its totient is φ = 81166468.

The previous prime is 81166457. The next prime is 81166489. The reversal of 81166469 is 96466118.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 44382244 + 36784225 = 6662^2 + 6065^2 .

It is a cyclic number.

It is not a de Polignac number, because 81166469 - 2⁴ = 81166453 is a prime.

It is a super-2 number, since 2×81166469² = 13175991379855922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81166439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40583234 + 40583235.

It is an arithmetic number, because the mean of its divisors is an integer number (40583235).

Almost surely, 2^81166469 is an apocalyptic number.

It is an amenable number.

81166469 is a deficient number, since it is larger than the sum of its proper divisors (1).

81166469 is an equidigital number, since it uses as much as digits as its factorization.

81166469 is an evil number, because the sum of its binary digits is even.

The product of its digits is 62208, while the sum is 41.

The square root of 81166469 is about 9009.2435309520. The cubic root of 81166469 is about 432.9710754822.

The spelling of 81166469 in words is "eighty-one million, one hundred sixty-six thousand, four hundred sixty-nine".