81774169 has 4 divisors (see below), whose sum is σ = 81796660. Its totient is φ = 81751680.

The previous prime is 81774163. The next prime is 81774197. The reversal of 81774169 is 96147718.

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 36144144 + 45630025 = 6012^2 + 6755^2 .

It is a cyclic number.

It is not a de Polignac number, because 81774169 - 2⁷ = 81774041 is a prime.

It is a super-2 number, since 2×81774169² = 13374029431281122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81774163) 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, 4404 + ... + 13525.

It is an arithmetic number, because the mean of its divisors is an integer number (20449165).

Almost surely, 2^81774169 is an apocalyptic number.

It is an amenable number.

81774169 is a deficient number, since it is larger than the sum of its proper divisors (22491).

81774169 is a wasteful number, since it uses less digits than its factorization.

81774169 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22490.

The product of its digits is 84672, while the sum is 43.

The square root of 81774169 is about 9042.9071099951. The cubic root of 81774169 is about 434.0489531875.

The spelling of 81774169 in words is "eighty-one million, seven hundred seventy-four thousand, one hundred sixty-nine".