81862559 has 4 divisors (see below), whose sum is σ = 83250120. Its totient is φ = 80475000.

The previous prime is 81862541. The next prime is 81862619. The reversal of 81862559 is 95526818.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81862559 - 2¹² = 81858463 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81862159) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 693692 + ... + 693809.

It is an arithmetic number, because the mean of its divisors is an integer number (20812530).

Almost surely, 2^81862559 is an apocalyptic number.

81862559 is a deficient number, since it is larger than the sum of its proper divisors (1387561).

81862559 is a wasteful number, since it uses less digits than its factorization.

81862559 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1387560.

The product of its digits is 172800, while the sum is 44.

The square root of 81862559 is about 9047.7930458206. The cubic root of 81862559 is about 434.2052852443.

The spelling of 81862559 in words is "eighty-one million, eight hundred sixty-two thousand, five hundred fifty-nine".