81875511 has 6 divisors (see below), whose sum is σ = 118264640. Its totient is φ = 54583668.

The previous prime is 81875491. The next prime is 81875527. The reversal of 81875511 is 11557818.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-81875511 is a prime.

It is a super-2 number, since 2×81875511² = 13407198603022242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81875411) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4548631 + ... + 4548648.

Almost surely, 2^81875511 is an apocalyptic number.

81875511 is a deficient number, since it is larger than the sum of its proper divisors (36389129).

81875511 is a wasteful number, since it uses less digits than its factorization.

81875511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9097285 (or 9097282 counting only the distinct ones).

The product of its digits is 11200, while the sum is 36.

The square root of 81875511 is about 9048.5087721679. The cubic root of 81875511 is about 434.2281835035.

The spelling of 81875511 in words is "eighty-one million, eight hundred seventy-five thousand, five hundred eleven".