81035391 has 4 divisors (see below), whose sum is σ = 108047192. Its totient is φ = 54023592.

The previous prime is 81035377. The next prime is 81035401. The reversal of 81035391 is 19353018.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 81035391 - 2⁹ = 81034879 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81035791) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13505896 + ... + 13505901.

It is an arithmetic number, because the mean of its divisors is an integer number (27011798).

Almost surely, 2^81035391 is an apocalyptic number.

81035391 is a deficient number, since it is larger than the sum of its proper divisors (27011801).

81035391 is a wasteful number, since it uses less digits than its factorization.

81035391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27011800.

The product of its (nonzero) digits is 3240, while the sum is 30.

The square root of 81035391 is about 9001.9659519463. The cubic root of 81035391 is about 432.7378775396.

The spelling of 81035391 in words is "eighty-one million, thirty-five thousand, three hundred ninety-one".