81887539 has 2 divisors, whose sum is σ = 81887540. Its totient is φ = 81887538.

The previous prime is 81887527. The next prime is 81887543. The reversal of 81887539 is 93578818.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81887539 - 2¹¹ = 81885491 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81887492 and 81887501.

It is not a weakly prime, because it can be changed into another prime (81887579) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40943769 + 40943770.

It is an arithmetic number, because the mean of its divisors is an integer number (40943770).

Almost surely, 2^81887539 is an apocalyptic number.

81887539 is a deficient number, since it is larger than the sum of its proper divisors (1).

81887539 is an equidigital number, since it uses as much as digits as its factorization.

81887539 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 483840, while the sum is 49.

The square root of 81887539 is about 9049.1733876636. The cubic root of 81887539 is about 434.2494460308.

The spelling of 81887539 in words is "eighty-one million, eight hundred eighty-seven thousand, five hundred thirty-nine".