81570380 has 48 divisors (see below), whose sum is σ = 176795136. Its totient is φ = 31596480.

The previous prime is 81570373. The next prime is 81570389. The reversal of 81570380 is 8307518.

It is not an unprimeable number, because it can be changed into a prime (81570389) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 100175 + ... + 100985.

It is an arithmetic number, because the mean of its divisors is an integer number (3683232).

Almost surely, 2^81570380 is an apocalyptic number.

It is an amenable number.

81570380 is an abundant number, since it is smaller than the sum of its proper divisors (95224756).

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

81570380 is a wasteful number, since it uses less digits than its factorization.

81570380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 974 (or 972 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 32.

The square root of 81570380 is about 9031.6321891450. The cubic root of 81570380 is about 433.6880895063.

Adding to 81570380 its reverse (8307518), we get a palindrome (89877898).

The spelling of 81570380 in words is "eighty-one million, five hundred seventy thousand, three hundred eighty".