81312858 has 24 divisors (see below), whose sum is σ = 192194496. Its totient is φ = 24640200.

The previous prime is 81312827. The next prime is 81312863. The reversal of 81312858 is 85821318.

It is a super-2 number, since 2×81312858² = 13223561752256328, which contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 205138 + ... + 205533.

It is an arithmetic number, because the mean of its divisors is an integer number (8008104).

Almost surely, 2^81312858 is an apocalyptic number.

81312858 is an abundant number, since it is smaller than the sum of its proper divisors (110881638).

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

81312858 is a wasteful number, since it uses less digits than its factorization.

81312858 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 410690 (or 410687 counting only the distinct ones).

The product of its digits is 15360, while the sum is 36.

The square root of 81312858 is about 9017.3642490475. The cubic root of 81312858 is about 433.2312163057.

The spelling of 81312858 in words is "eighty-one million, three hundred twelve thousand, eight hundred fifty-eight".