81555782 has 32 divisors (see below), whose sum is σ = 152941824. Its totient is φ = 31687200.

The previous prime is 81555751. The next prime is 81555791. The reversal of 81555782 is 28755518.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 100157 + ... + 100967.

It is an arithmetic number, because the mean of its divisors is an integer number (4779432).

Almost surely, 2^81555782 is an apocalyptic number.

81555782 is a deficient number, since it is larger than the sum of its proper divisors (71386042).

81555782 is a wasteful number, since it uses less digits than its factorization.

81555782 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1484.

The product of its digits is 112000, while the sum is 41.

The square root of 81555782 is about 9030.8239934128. The cubic root of 81555782 is about 433.6622167306.

The spelling of 81555782 in words is "eighty-one million, five hundred fifty-five thousand, seven hundred eighty-two".