81840577 has 16 divisors (see below), whose sum is σ = 101001600. Its totient is φ = 64576512.

The previous prime is 81840569. The next prime is 81840587. The reversal of 81840577 is 77504818.

It is not a de Polignac number, because 81840577 - 2³ = 81840569 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81840557) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 39858 + ... + 41860.

It is an arithmetic number, because the mean of its divisors is an integer number (6312600).

Almost surely, 2^81840577 is an apocalyptic number.

It is an amenable number.

81840577 is a deficient number, since it is larger than the sum of its proper divisors (19161023).

81840577 is a wasteful number, since it uses less digits than its factorization.

81840577 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2472.

The product of its (nonzero) digits is 62720, while the sum is 40.

The square root of 81840577 is about 9046.5781928860. The cubic root of 81840577 is about 434.1664170277.

The spelling of 81840577 in words is "eighty-one million, eight hundred forty thousand, five hundred seventy-seven".