81057270 has 96 divisors (see below), whose sum is σ = 229955328. Its totient is φ = 18228672.

The previous prime is 81057259. The next prime is 81057271. The reversal of 81057270 is 7275018.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81057271) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 98079 + ... + 98901.

It is an arithmetic number, because the mean of its divisors is an integer number (2395368).

Almost surely, 2^81057270 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81057270, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (114977664).

81057270 is an abundant number, since it is smaller than the sum of its proper divisors (148898058).

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

81057270 is a wasteful number, since it uses less digits than its factorization.

81057270 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 914 (or 907 counting only the distinct ones).

The product of its (nonzero) digits is 3920, while the sum is 30.

The square root of 81057270 is about 9003.1811044764. The cubic root of 81057270 is about 432.7768194552.

The spelling of 81057270 in words is "eighty-one million, fifty-seven thousand, two hundred seventy".