81863375 has 32 divisors (see below), whose sum is σ = 115352640. Its totient is φ = 57456000.

The previous prime is 81863363. The next prime is 81863407. The reversal of 81863375 is 57336818.

It is not a de Polignac number, because 81863375 - 2⁴ = 81863359 is a prime.

It is a super-2 number, since 2×81863375² = 13403224332781250, 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 (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 38849 + ... + 40901.

It is an arithmetic number, because the mean of its divisors is an integer number (3604770).

Almost surely, 2^81863375 is an apocalyptic number.

81863375 is a deficient number, since it is larger than the sum of its proper divisors (33489265).

81863375 is a wasteful number, since it uses less digits than its factorization.

81863375 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2108 (or 2098 counting only the distinct ones).

The product of its digits is 120960, while the sum is 41.

The square root of 81863375 is about 9047.8381395779. The cubic root of 81863375 is about 434.2067279483.

The spelling of 81863375 in words is "eighty-one million, eight hundred sixty-three thousand, three hundred seventy-five".