81370186 has 8 divisors (see below), whose sum is σ = 122099364. Its totient is φ = 40670400.

The previous prime is 81370169. The next prime is 81370213. The reversal of 81370186 is 68107318.

It can be written as a sum of positive squares in 2 ways, for example, as 77105961 + 4264225 = 8781^2 + 2065^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×81370186² = 13242214339349192, which contains 22 as substring.

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 3 ways as a sum of consecutive naturals, for example, 1906 + ... + 12898.

Almost surely, 2^81370186 is an apocalyptic number.

81370186 is a deficient number, since it is larger than the sum of its proper divisors (40729178).

81370186 is a wasteful number, since it uses less digits than its factorization.

81370186 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14696.

The product of its (nonzero) digits is 8064, while the sum is 34.

The square root of 81370186 is about 9020.5424448866. The cubic root of 81370186 is about 433.3330060484. Note that the first 3 decimals are identical.

The spelling of 81370186 in words is "eighty-one million, three hundred seventy thousand, one hundred eighty-six".