81985158 has 24 divisors (see below), whose sum is σ = 181968696. Its totient is φ = 26661600.

The previous prime is 81985151. The next prime is 81985177. The reversal of 81985158 is 85158918.

It is a super-2 number, since 2×81985158² = 13443132264569928, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81985151) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 54808 + ... + 56283.

It is an arithmetic number, because the mean of its divisors is an integer number (7582029).

Almost surely, 2^81985158 is an apocalyptic number.

81985158 is an abundant number, since it is smaller than the sum of its proper divisors (99983538).

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

81985158 is a wasteful number, since it uses less digits than its factorization.

81985158 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111140 (or 111137 counting only the distinct ones).

The product of its digits is 115200, while the sum is 45.

The square root of 81985158 is about 9054.5655886961. The cubic root of 81985158 is about 434.4219352903.

The spelling of 81985158 in words is "eighty-one million, nine hundred eighty-five thousand, one hundred fifty-eight".