81158775 has 48 divisors (see below), whose sum is σ = 140848128. Its totient is φ = 41184000.

The previous prime is 81158761. The next prime is 81158839. The reversal of 81158775 is 57785118.

It is not a de Polignac number, because 81158775 - 2⁷ = 81158647 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 155515 + ... + 156035.

It is an arithmetic number, because the mean of its divisors is an integer number (2934336).

Almost surely, 2^81158775 is an apocalyptic number.

81158775 is a deficient number, since it is larger than the sum of its proper divisors (59689353).

81158775 is a wasteful number, since it uses less digits than its factorization.

81158775 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 632 (or 627 counting only the distinct ones).

The product of its digits is 78400, while the sum is 42.

The square root of 81158775 is about 9008.8165149480. The cubic root of 81158775 is about 432.9573941975.

The spelling of 81158775 in words is "eighty-one million, one hundred fifty-eight thousand, seven hundred seventy-five".