81487687 has 2 divisors, whose sum is σ = 81487688. Its totient is φ = 81487686.

The previous prime is 81487649. The next prime is 81487691. The reversal of 81487687 is 78678418.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81487687 - 2⁷ = 81487559 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81487687.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81487697) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40743843 + 40743844.

It is an arithmetic number, because the mean of its divisors is an integer number (40743844).

Almost surely, 2^81487687 is an apocalyptic number.

81487687 is a deficient number, since it is larger than the sum of its proper divisors (1).

81487687 is an equidigital number, since it uses as much as digits as its factorization.

81487687 is an evil number, because the sum of its binary digits is even.

The product of its digits is 602112, while the sum is 49.

The square root of 81487687 is about 9027.0530628772. The cubic root of 81487687 is about 433.5414877012.

The spelling of 81487687 in words is "eighty-one million, four hundred eighty-seven thousand, six hundred eighty-seven".