81464165 has 4 divisors (see below), whose sum is σ = 97757004. Its totient is φ = 65171328.

The previous prime is 81464107. The next prime is 81464177. The reversal of 81464165 is 56146418.

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 18515809 + 62948356 = 4303^2 + 7934^2 .

It is a cyclic number.

It is not a de Polignac number, because 81464165 - 2⁶ = 81464101 is a prime.

It is a Duffinian number.

It is a congruent 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, 8146412 + ... + 8146421.

It is an arithmetic number, because the mean of its divisors is an integer number (24439251).

Almost surely, 2^81464165 is an apocalyptic number.

It is an amenable number.

81464165 is a deficient number, since it is larger than the sum of its proper divisors (16292839).

81464165 is a wasteful number, since it uses less digits than its factorization.

81464165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16292838.

The product of its digits is 23040, while the sum is 35.

The square root of 81464165 is about 9025.7501073318. The cubic root of 81464165 is about 433.4997687429.

The spelling of 81464165 in words is "eighty-one million, four hundred sixty-four thousand, one hundred sixty-five".