81040369 has 2 divisors, whose sum is σ = 81040370. Its totient is φ = 81040368.

The previous prime is 81040331. The next prime is 81040373. The reversal of 81040369 is 96304018.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 62204769 + 18835600 = 7887^2 + 4340^2 .

It is a cyclic number.

It is not a de Polignac number, because 81040369 - 2⁹ = 81039857 is a prime.

It is a super-2 number, since 2×81040369² = 13135082815312322, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81040369.

It is not a weakly prime, because it can be changed into another prime (81040469) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40520184 + 40520185.

It is an arithmetic number, because the mean of its divisors is an integer number (40520185).

Almost surely, 2^81040369 is an apocalyptic number.

It is an amenable number.

81040369 is a deficient number, since it is larger than the sum of its proper divisors (1).

81040369 is an equidigital number, since it uses as much as digits as its factorization.

81040369 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 81040369 is about 9002.2424428583. The cubic root of 81040369 is about 432.7467383802.

The spelling of 81040369 in words is "eighty-one million, forty thousand, three hundred sixty-nine".