81847719 has 16 divisors (see below), whose sum is σ = 125168640. Its totient is φ = 52804440.

The previous prime is 81847699. The next prime is 81847723. The reversal of 81847719 is 91774818.

It is not a de Polignac number, because 81847719 - 2⁸ = 81847463 is a prime.

It is a super-2 number, since 2×81847719² = 13398098211005922, which contains 22 as substring.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81847729) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 48057 + ... + 49730.

It is an arithmetic number, because the mean of its divisors is an integer number (7823040).

Almost surely, 2^81847719 is an apocalyptic number.

81847719 is a deficient number, since it is larger than the sum of its proper divisors (43320921).

81847719 is a wasteful number, since it uses less digits than its factorization.

81847719 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97827 (or 97821 counting only the distinct ones).

The product of its digits is 112896, while the sum is 45.

The square root of 81847719 is about 9046.9729191592. The cubic root of 81847719 is about 434.1790461597.

The spelling of 81847719 in words is "eighty-one million, eight hundred forty-seven thousand, seven hundred nineteen".