81574866 has 48 divisors (see below), whose sum is σ = 188042400. Its totient is φ = 25484544.

The previous prime is 81574861. The next prime is 81574877. The reversal of 81574866 is 66847518.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81574861) 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, 31945 + ... + 34403.

It is an arithmetic number, because the mean of its divisors is an integer number (3917550).

Almost surely, 2^81574866 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81574866, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (94021200).

81574866 is an abundant number, since it is smaller than the sum of its proper divisors (106467534).

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

81574866 is a wasteful number, since it uses less digits than its factorization.

81574866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2583 (or 2580 counting only the distinct ones).

The product of its digits is 322560, while the sum is 45.

The square root of 81574866 is about 9031.8805350824. The cubic root of 81574866 is about 433.6960396516.

The spelling of 81574866 in words is "eighty-one million, five hundred seventy-four thousand, eight hundred sixty-six".