81006875 has 40 divisors (see below), whose sum is σ = 108265344. Its totient is φ = 60480000.

The previous prime is 81006839. The next prime is 81006907. The reversal of 81006875 is 57860018.

It is a happy number.

It is not a de Polignac number, because 81006875 - 2⁸ = 81006619 is a prime.

It is a super-2 number, since 2×81006875² = 13124227594531250, which contains 22 as substring.

It is a Duffinian 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 39 ways as a sum of consecutive naturals, for example, 716819 + ... + 716931.

Almost surely, 2^81006875 is an apocalyptic number.

81006875 is a deficient number, since it is larger than the sum of its proper divisors (27258469).

81006875 is a wasteful number, since it uses less digits than its factorization.

81006875 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 201 (or 186 counting only the distinct ones).

The product of its (nonzero) digits is 13440, while the sum is 35.

The square root of 81006875 is about 9000.3819363403. The cubic root of 81006875 is about 432.6871120617.

The spelling of 81006875 in words is "eighty-one million, six thousand, eight hundred seventy-five".