81997255 has 16 divisors (see below), whose sum is σ = 104140800. Its totient is φ = 61806240.

The previous prime is 81997249. The next prime is 81997271. The reversal of 81997255 is 55279918.

It is not a de Polignac number, because 81997255 - 2³ = 81997247 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15886 + ... + 20404.

It is an arithmetic number, because the mean of its divisors is an integer number (6508800).

Almost surely, 2^81997255 is an apocalyptic number.

81997255 is a deficient number, since it is larger than the sum of its proper divisors (22143545).

81997255 is a wasteful number, since it uses less digits than its factorization.

81997255 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4734.

The product of its digits is 226800, while the sum is 46.

The square root of 81997255 is about 9055.2335695994. The cubic root of 81997255 is about 434.4433007172.

The spelling of 81997255 in words is "eighty-one million, nine hundred ninety-seven thousand, two hundred fifty-five".