81593168 has 20 divisors (see below), whose sum is σ = 158475348. Its totient is φ = 40696320.

The previous prime is 81593159. The next prime is 81593189. The reversal of 81593168 is 86139518.

It can be written as a sum of positive squares in 2 ways, for example, as 8456464 + 73136704 = 2908^2 + 8552^2 .

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 in 3 ways as a sum of consecutive naturals, for example, 680 + ... + 12792.

Almost surely, 2^81593168 is an apocalyptic number.

It is an amenable number.

81593168 is a deficient number, since it is larger than the sum of its proper divisors (76882180).

81593168 is a wasteful number, since it uses less digits than its factorization.

81593168 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12542 (or 12536 counting only the distinct ones).

The product of its digits is 51840, while the sum is 41.

The square root of 81593168 is about 9032.8936670372. The cubic root of 81593168 is about 433.7284716647.

The spelling of 81593168 in words is "eighty-one million, five hundred ninety-three thousand, one hundred sixty-eight".