81775798 has 8 divisors (see below), whose sum is σ = 132099408. Its totient is φ = 37742664.

The previous prime is 81775789. The next prime is 81775801. The reversal of 81775798 is 89757718.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×81775798² = 13374562277073608, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1572586 + ... + 1572637.

It is an arithmetic number, because the mean of its divisors is an integer number (16512426).

Almost surely, 2^81775798 is an apocalyptic number.

81775798 is a deficient number, since it is larger than the sum of its proper divisors (50323610).

81775798 is a wasteful number, since it uses less digits than its factorization.

81775798 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3145238.

The product of its digits is 987840, while the sum is 52.

The square root of 81775798 is about 9042.9971801389. The cubic root of 81775798 is about 434.0518353570.

The spelling of 81775798 in words is "eighty-one million, seven hundred seventy-five thousand, seven hundred ninety-eight".