81582858 has 96 divisors (see below), whose sum is σ = 212284800. Its totient is φ = 22151808.

The previous prime is 81582857. The next prime is 81582859. The reversal of 81582858 is 85828518.

It is an interprime number because it is at equal distance from previous prime (81582857) and next prime (81582859).

It is not an unprimeable number, because it can be changed into a prime (81582857) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 303148 + ... + 303416.

It is an arithmetic number, because the mean of its divisors is an integer number (2211300).

Almost surely, 2^81582858 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81582858, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (106142400).

81582858 is an abundant number, since it is smaller than the sum of its proper divisors (130701942).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81582858 is a wasteful number, since it uses less digits than its factorization.

81582858 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 396 (or 393 counting only the distinct ones).

The product of its digits is 204800, while the sum is 45.

The square root of 81582858 is about 9032.3229570250. The cubic root of 81582858 is about 433.7102024517.

The spelling of 81582858 in words is "eighty-one million, five hundred eighty-two thousand, eight hundred fifty-eight".