81432570 has 16 divisors (see below), whose sum is σ = 195438240. Its totient is φ = 21715344.

The previous prime is 81432553. The next prime is 81432577. The reversal of 81432570 is 7523418.

It is a Harshad number since it is a multiple of its sum of digits (30), and also a Moran number because the ratio is a prime number: 2714419 = 81432570 / (8 + 1 + 4 + 3 + 2 + 5 + 7 + 0).

It is not an unprimeable number, because it can be changed into a prime (81432577) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1357180 + ... + 1357239.

It is an arithmetic number, because the mean of its divisors is an integer number (12214890).

Almost surely, 2^81432570 is an apocalyptic number.

81432570 is an abundant number, since it is smaller than the sum of its proper divisors (114005670).

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

81432570 is a wasteful number, since it uses less digits than its factorization.

81432570 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2714429.

The product of its (nonzero) digits is 6720, while the sum is 30.

The square root of 81432570 is about 9023.9996675532. Note that the first 3 decimals coincide. The cubic root of 81432570 is about 433.4437187556.

Adding to 81432570 its reverse (7523418), we get a palindrome (88955988).

The spelling of 81432570 in words is "eighty-one million, four hundred thirty-two thousand, five hundred seventy".