81573858 has 32 divisors (see below), whose sum is σ = 185137920. Its totient is φ = 26611920.

The previous prime is 81573857. The next prime is 81573913. The reversal of 81573858 is 85837518.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (81573857) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13533 + ... + 18608.

It is an arithmetic number, because the mean of its divisors is an integer number (5785560).

Almost surely, 2^81573858 is an apocalyptic number.

81573858 is an abundant number, since it is smaller than the sum of its proper divisors (103564062).

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

81573858 is a wasteful number, since it uses less digits than its factorization.

81573858 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32199 (or 32193 counting only the distinct ones).

The product of its digits is 268800, while the sum is 45.

The square root of 81573858 is about 9031.8247325776. The cubic root of 81573858 is about 433.6942532868.

The spelling of 81573858 in words is "eighty-one million, five hundred seventy-three thousand, eight hundred fifty-eight".