81000635 has 4 divisors (see below), whose sum is σ = 97200768. Its totient is φ = 64800504.

The previous prime is 81000593. The next prime is 81000643. The reversal of 81000635 is 53600018.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 53600018 = 2 ⋅26800009.

It is a cyclic number.

It is not a de Polignac number, because 81000635 - 2⁶ = 81000571 is a prime.

It is a super-2 number, since 2×81000635² = 13122205740806450, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81000635.

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, 8100059 + ... + 8100068.

It is an arithmetic number, because the mean of its divisors is an integer number (24300192).

Almost surely, 2^81000635 is an apocalyptic number.

81000635 is a deficient number, since it is larger than the sum of its proper divisors (16200133).

81000635 is a wasteful number, since it uses less digits than its factorization.

81000635 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16200132.

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 81000635 is about 9000.0352777086. The cubic root of 81000635 is about 432.6760017417.

The spelling of 81000635 in words is "eighty-one million, six hundred thirty-five", and thus it is an aban number.