81858959 has 24 divisors (see below), whose sum is σ = 103593168. Its totient is φ = 64108800.

The previous prime is 81858947. The next prime is 81858989. The reversal of 81858959 is 95985818.

It is not a de Polignac number, because 81858959 - 2⁴ = 81858943 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81858959.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81858989) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 67559 + ... + 68759.

It is an arithmetic number, because the mean of its divisors is an integer number (4316382).

Almost surely, 2^81858959 is an apocalyptic number.

81858959 is a deficient number, since it is larger than the sum of its proper divisors (21734209).

81858959 is a wasteful number, since it uses less digits than its factorization.

81858959 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1335 (or 1328 counting only the distinct ones).

The product of its digits is 1036800, while the sum is 53.

The square root of 81858959 is about 9047.5941000909. The cubic root of 81858959 is about 434.1989202590.

The spelling of 81858959 in words is "eighty-one million, eight hundred fifty-eight thousand, nine hundred fifty-nine".