81366770 has 8 divisors (see below), whose sum is σ = 146460204. Its totient is φ = 32546704.

The previous prime is 81366767. The next prime is 81366773. The reversal of 81366770 is 7766318.

It is an interprime number because it is at equal distance from previous prime (81366767) and next prime (81366773).

It can be written as a sum of positive squares in 2 ways, for example, as 73908409 + 7458361 = 8597^2 + 2731^2 .

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

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81366773) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4068329 + ... + 4068348.

Almost surely, 2^81366770 is an apocalyptic number.

81366770 is a deficient number, since it is larger than the sum of its proper divisors (65093434).

81366770 is a wasteful number, since it uses less digits than its factorization.

81366770 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8136684.

The product of its (nonzero) digits is 42336, while the sum is 38.

The square root of 81366770 is about 9020.3530973017. The cubic root of 81366770 is about 433.3269420491.

The spelling of 81366770 in words is "eighty-one million, three hundred sixty-six thousand, seven hundred seventy".