81751155 has 16 divisors (see below), whose sum is σ = 130918560. Its totient is φ = 43561728.

The previous prime is 81751139. The next prime is 81751157. The reversal of 81751155 is 55115718.

It is not a de Polignac number, because 81751155 - 2⁴ = 81751139 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81751157) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 24741 + ... + 27849.

It is an arithmetic number, because the mean of its divisors is an integer number (8182410).

Almost surely, 2^81751155 is an apocalyptic number.

81751155 is a deficient number, since it is larger than the sum of its proper divisors (49167405).

81751155 is a wasteful number, since it uses less digits than its factorization.

81751155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4870.

The product of its digits is 7000, while the sum is 33.

The square root of 81751155 is about 9041.6345314329. The cubic root of 81751155 is about 434.0082307117.

The spelling of 81751155 in words is "eighty-one million, seven hundred fifty-one thousand, one hundred fifty-five".