81898975 has 12 divisors (see below), whose sum is σ = 105970896. Its totient is φ = 62670080.

The previous prime is 81898969. The next prime is 81899009. The reversal of 81898975 is 57989818.

It is not a de Polignac number, because 81898975 - 2¹⁹ = 81374687 is a prime.

It is a Duffinian number.

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 11 ways as a sum of consecutive naturals, for example, 70642 + ... + 71791.

It is an arithmetic number, because the mean of its divisors is an integer number (8830908).

Almost surely, 2^81898975 is an apocalyptic number.

81898975 is a deficient number, since it is larger than the sum of its proper divisors (24071921).

81898975 is a wasteful number, since it uses less digits than its factorization.

81898975 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 142466 (or 142461 counting only the distinct ones).

The product of its digits is 1451520, while the sum is 55.

The square root of 81898975 is about 9049.8052465233. The cubic root of 81898975 is about 434.2696601177.

The spelling of 81898975 in words is "eighty-one million, eight hundred ninety-eight thousand, nine hundred seventy-five".