81969365 has 8 divisors (see below), whose sum is σ = 99377880. Its totient is φ = 64899072.

The previous prime is 81969331. The next prime is 81969367. The reversal of 81969365 is 56396918.

It can be written as a sum of positive squares in 4 ways, for example, as 4986289 + 76983076 = 2233^2 + 8774^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81969365 - 2¹² = 81965269 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81969367) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 84020 + ... + 84989.

It is an arithmetic number, because the mean of its divisors is an integer number (12422235).

Almost surely, 2^81969365 is an apocalyptic number.

It is an amenable number.

81969365 is a deficient number, since it is larger than the sum of its proper divisors (17408515).

81969365 is a wasteful number, since it uses less digits than its factorization.

81969365 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169111.

The product of its digits is 349920, while the sum is 47.

The square root of 81969365 is about 9053.6934452189. The cubic root of 81969365 is about 434.3940389150.

The spelling of 81969365 in words is "eighty-one million, nine hundred sixty-nine thousand, three hundred sixty-five".