81786304309 has 32 divisors (see below), whose sum is σ = 91429502976. Its totient is φ = 72825661440.

The previous prime is 81786304297. The next prime is 81786304319. The reversal of 81786304309 is 90340368718.

It is a happy number.

It is not a de Polignac number, because 81786304309 - 2¹¹ = 81786302261 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81786304319) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3247564 + ... + 3272650.

It is an arithmetic number, because the mean of its divisors is an integer number (2857171968).

Almost surely, 2^81786304309 is an apocalyptic number.

It is an amenable number.

81786304309 is a deficient number, since it is larger than the sum of its proper divisors (9643198667).

81786304309 is a wasteful number, since it uses less digits than its factorization.

81786304309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25285.

The product of its (nonzero) digits is 870912, while the sum is 49.

The spelling of 81786304309 in words is "eighty-one billion, seven hundred eighty-six million, three hundred four thousand, three hundred nine".