81573044 has 36 divisors (see below), whose sum is σ = 167005440. Its totient is φ = 34760880.

The previous prime is 81573029. The next prime is 81573053. The reversal of 81573044 is 44037518.

It is a self number, because there is not a number n which added to its sum of digits gives 81573044.

It is a congruent 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, 36347 + ... + 38525.

It is an arithmetic number, because the mean of its divisors is an integer number (4639040).

Almost surely, 2^81573044 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81573044, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (83502720).

81573044 is an abundant number, since it is smaller than the sum of its proper divisors (85432396).

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

81573044 is a wasteful number, since it uses less digits than its factorization.

81573044 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2388 (or 2379 counting only the distinct ones).

The product of its (nonzero) digits is 13440, while the sum is 32.

The square root of 81573044 is about 9031.7796695889. The cubic root of 81573044 is about 433.6928107156.

The spelling of 81573044 in words is "eighty-one million, five hundred seventy-three thousand, forty-four".