81371069 has 16 divisors (see below), whose sum is σ = 89284272. Its totient is φ = 73709568.

The previous prime is 81371051. The next prime is 81371077. The reversal of 81371069 is 96017318.

It can be written as a sum of positive squares in 8 ways, for example, as 136900 + 81234169 = 370^2 + 9013^2 .

It is a cyclic number.

It is not a de Polignac number, because 81371069 - 2²⁰ = 80322493 is a prime.

It is a super-2 number, since 2×81371069² = 13242501740405522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81371669) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 217967 + ... + 218339.

It is an arithmetic number, because the mean of its divisors is an integer number (5580267).

Almost surely, 2^81371069 is an apocalyptic number.

It is an amenable number.

81371069 is a deficient number, since it is larger than the sum of its proper divisors (7913203).

81371069 is a wasteful number, since it uses less digits than its factorization.

81371069 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 656.

The product of its (nonzero) digits is 9072, while the sum is 35.

The square root of 81371069 is about 9020.5913885953. The cubic root of 81371069 is about 433.3345735007.

The spelling of 81371069 in words is "eighty-one million, three hundred seventy-one thousand, sixty-nine".