81841791 has 24 divisors (see below), whose sum is σ = 117787824. Its totient is φ = 50371840.

The previous prime is 81841789. The next prime is 81841801. The reversal of 81841791 is 19714818.

It is not a de Polignac number, because 81841791 - 2¹ = 81841789 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81841091) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 177301 + ... + 177761.

It is an arithmetic number, because the mean of its divisors is an integer number (4907826).

Almost surely, 2^81841791 is an apocalyptic number.

81841791 is a deficient number, since it is larger than the sum of its proper divisors (35946033).

81841791 is a wasteful number, since it uses less digits than its factorization.

81841791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 599 (or 540 counting only the distinct ones).

The product of its digits is 16128, while the sum is 39.

The square root of 81841791 is about 9046.6452898298. The cubic root of 81841791 is about 434.1685637844.

The spelling of 81841791 in words is "eighty-one million, eight hundred forty-one thousand, seven hundred ninety-one".