81855475 has 24 divisors (see below), whose sum is σ = 111992832. Its totient is φ = 58963200.

The previous prime is 81855467. The next prime is 81855491. The reversal of 81855475 is 57455818.

It is not a de Polignac number, because 81855475 - 2³ = 81855467 is a prime.

It is a super-3 number, since 3×81855475³ (a number of 25 digits) contains 333 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 (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10254 + ... + 16396.

It is an arithmetic number, because the mean of its divisors is an integer number (4666368).

Almost surely, 2^81855475 is an apocalyptic number.

81855475 is a deficient number, since it is larger than the sum of its proper divisors (30137357).

81855475 is a wasteful number, since it uses less digits than its factorization.

81855475 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6207 (or 6202 counting only the distinct ones).

The product of its digits is 224000, while the sum is 43.

The square root of 81855475 is about 9047.4015606692. The cubic root of 81855475 is about 434.1927601901.

The spelling of 81855475 in words is "eighty-one million, eight hundred fifty-five thousand, four hundred seventy-five".