81129693 has 8 divisors (see below), whose sum is σ = 110811456. Its totient is φ = 52767200.

The previous prime is 81129679. The next prime is 81129703. The reversal of 81129693 is 39692118.

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 81129693 - 2⁸ = 81129437 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81129623) 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, 329673 + ... + 329918.

It is an arithmetic number, because the mean of its divisors is an integer number (13851432).

Almost surely, 2^81129693 is an apocalyptic number.

It is an amenable number.

81129693 is a deficient number, since it is larger than the sum of its proper divisors (29681763).

81129693 is a wasteful number, since it uses less digits than its factorization.

81129693 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 659635.

The product of its digits is 23328, while the sum is 39.

The square root of 81129693 is about 9007.2022848385. The cubic root of 81129693 is about 432.9056734759.

The spelling of 81129693 in words is "eighty-one million, one hundred twenty-nine thousand, six hundred ninety-three".