81182705 has 4 divisors (see below), whose sum is σ = 97419252. Its totient is φ = 64946160.

The previous prime is 81182683. The next prime is 81182713. The reversal of 81182705 is 50728118.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 25411681 + 55771024 = 5041^2 + 7468^2 .

It is not a de Polignac number, because 81182705 - 2¹² = 81178609 is a prime.

It is a super-2 number, since 2×81182705² = 13181263182234050, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8118266 + ... + 8118275.

It is an arithmetic number, because the mean of its divisors is an integer number (24354813).

Almost surely, 2^81182705 is an apocalyptic number.

It is an amenable number.

81182705 is a deficient number, since it is larger than the sum of its proper divisors (16236547).

81182705 is a wasteful number, since it uses less digits than its factorization.

81182705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16236546.

The product of its (nonzero) digits is 4480, while the sum is 32.

The square root of 81182705 is about 9010.1445604385. The cubic root of 81182705 is about 432.9999431078. Note that the first 4 decimals are identical.

Adding to 81182705 its sum of digits (32), we get a cube (81182737 = 433³).

The spelling of 81182705 in words is "eighty-one million, one hundred eighty-two thousand, seven hundred five".