81487789 has 12 divisors (see below), whose sum is σ = 87236800. Its totient is φ = 75894624.

The previous prime is 81487771. The next prime is 81487799. The reversal of 81487789 is 98778418.

It is not a de Polignac number, because 81487789 - 2¹⁵ = 81455021 is a prime.

It is a super-2 number, since 2×81487789² = 13280519512217042, 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 (81487739) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 349617 + ... + 349849.

Almost surely, 2^81487789 is an apocalyptic number.

It is an amenable number.

81487789 is a deficient number, since it is larger than the sum of its proper divisors (5749011).

81487789 is an equidigital number, since it uses as much as digits as its factorization.

81487789 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 564 (or 331 counting only the distinct ones).

The product of its digits is 903168, while the sum is 52.

The square root of 81487789 is about 9027.0587125597. The cubic root of 81487789 is about 433.5416685924.

The spelling of 81487789 in words is "eighty-one million, four hundred eighty-seven thousand, seven hundred eighty-nine".