81807736 has 8 divisors (see below), whose sum is σ = 153389520. Its totient is φ = 40903864.

The previous prime is 81807709. The next prime is 81807767. The reversal of 81807736 is 63770818.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 5112976 + ... + 5112991.

It is an arithmetic number, because the mean of its divisors is an integer number (19173690).

Almost surely, 2^81807736 is an apocalyptic number.

It is an amenable number.

81807736 is a deficient number, since it is larger than the sum of its proper divisors (71581784).

81807736 is a wasteful number, since it uses less digits than its factorization.

81807736 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10225973 (or 10225969 counting only the distinct ones).

The product of its (nonzero) digits is 56448, while the sum is 40.

The square root of 81807736 is about 9044.7629045763. The cubic root of 81807736 is about 434.1083351345.

The spelling of 81807736 in words is "eighty-one million, eight hundred seven thousand, seven hundred thirty-six".