81366369 has 32 divisors (see below), whose sum is σ = 133539840. Its totient is φ = 43007232.

The previous prime is 81366323. The next prime is 81366377. The reversal of 81366369 is 96366318.

It is not a de Polignac number, because 81366369 - 2⁹ = 81365857 is a prime.

It is a super-2 number, since 2×81366369² = 13240972008488322, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81366369.

It is not an unprimeable number, because it can be changed into a prime (81366169) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 19132 + ... + 22994.

It is an arithmetic number, because the mean of its divisors is an integer number (4173120).

Almost surely, 2^81366369 is an apocalyptic number.

It is an amenable number.

81366369 is a deficient number, since it is larger than the sum of its proper divisors (52173471).

81366369 is a wasteful number, since it uses less digits than its factorization.

81366369 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3949.

The product of its digits is 139968, while the sum is 42.

The square root of 81366369 is about 9020.3308697630. The cubic root of 81366369 is about 433.3262301926.

The spelling of 81366369 in words is "eighty-one million, three hundred sixty-six thousand, three hundred sixty-nine".