81187589 has 16 divisors (see below), whose sum is σ = 98918400. Its totient is φ = 65083824.

The previous prime is 81187571. The next prime is 81187619. The reversal of 81187589 is 98578118.

It is a cyclic number.

It is not a de Polignac number, because 81187589 - 2⁸ = 81187333 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81187549) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6644 + ... + 14370.

It is an arithmetic number, because the mean of its divisors is an integer number (6182400).

Almost surely, 2^81187589 is an apocalyptic number.

It is an amenable number.

81187589 is a deficient number, since it is larger than the sum of its proper divisors (17730811).

81187589 is a wasteful number, since it uses less digits than its factorization.

81187589 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7832.

The product of its digits is 161280, while the sum is 47.

The square root of 81187589 is about 9010.4155842003. The cubic root of 81187589 is about 433.0086261120.

The spelling of 81187589 in words is "eighty-one million, one hundred eighty-seven thousand, five hundred eighty-nine".