81091707 has 8 divisors (see below), whose sum is σ = 108313920. Its totient is φ = 53965320.

The previous prime is 81091687. The next prime is 81091711. The reversal of 81091707 is 70719018.

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

It is a de Polignac number, because none of the positive numbers 2^k-81091707 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81091607) 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, 21957 + ... + 25382.

It is an arithmetic number, because the mean of its divisors is an integer number (13539240).

Almost surely, 2^81091707 is an apocalyptic number.

81091707 is a deficient number, since it is larger than the sum of its proper divisors (27222213).

81091707 is a wasteful number, since it uses less digits than its factorization.

81091707 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47913.

The product of its (nonzero) digits is 3528, while the sum is 33.

The square root of 81091707 is about 9005.0933920754. The cubic root of 81091707 is about 432.8380988660.

The spelling of 81091707 in words is "eighty-one million, ninety-one thousand, seven hundred seven".