81540570 has 32 divisors (see below), whose sum is σ = 196725312. Its totient is φ = 21629952.

The previous prime is 81540559. The next prime is 81540577. The reversal of 81540570 is 7504518.

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

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81540577) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1252 + ... + 12831.

It is an arithmetic number, because the mean of its divisors is an integer number (6147666).

Almost surely, 2^81540570 is an apocalyptic number.

81540570 is an abundant number, since it is smaller than the sum of its proper divisors (115184742).

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

81540570 is a wasteful number, since it uses less digits than its factorization.

81540570 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14286.

The product of its (nonzero) digits is 5600, while the sum is 30.

The square root of 81540570 is about 9029.9817275563. The cubic root of 81540570 is about 433.6352524465.

The spelling of 81540570 in words is "eighty-one million, five hundred forty thousand, five hundred seventy".