81677689 has 2 divisors, whose sum is σ = 81677690. Its totient is φ = 81677688.

The previous prime is 81677677. The next prime is 81677711. The reversal of 81677689 is 98677618.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 75342400 + 6335289 = 8680^2 + 2517^2 .

It is a cyclic number.

It is not a de Polignac number, because 81677689 - 2¹¹ = 81675641 is a prime.

It is not a weakly prime, because it can be changed into another prime (81674689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40838844 + 40838845.

It is an arithmetic number, because the mean of its divisors is an integer number (40838845).

Almost surely, 2^81677689 is an apocalyptic number.

It is an amenable number.

81677689 is a deficient number, since it is larger than the sum of its proper divisors (1).

81677689 is an equidigital number, since it uses as much as digits as its factorization.

81677689 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1016064, while the sum is 52.

The square root of 81677689 is about 9037.5709679095. The cubic root of 81677689 is about 433.8781840084.

The spelling of 81677689 in words is "eighty-one million, six hundred seventy-seven thousand, six hundred eighty-nine".