81850699391 has 8 divisors (see below), whose sum is σ = 88680922704. Its totient is φ = 75244417920.

The previous prime is 81850699379. The next prime is 81850699423. The reversal of 81850699391 is 19399605818.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81850699391 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81850699391.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81850659391) 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, 55984700 + ... + 55986161.

It is an arithmetic number, because the mean of its divisors is an integer number (11085115338).

Almost surely, 2^81850699391 is an apocalyptic number.

81850699391 is a deficient number, since it is larger than the sum of its proper divisors (6830223313).

81850699391 is a wasteful number, since it uses less digits than its factorization.

81850699391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111970921.

The product of its (nonzero) digits is 4199040, while the sum is 59.

The spelling of 81850699391 in words is "eighty-one billion, eight hundred fifty million, six hundred ninety-nine thousand, three hundred ninety-one".