81607140 has 72 divisors (see below), whose sum is σ = 262112760. Its totient is φ = 20481024.

The previous prime is 81607117. The next prime is 81607153. The reversal of 81607140 is 4170618.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 42068196 + 39538944 = 6486^2 + 6288^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10275 + ... + 16394.

It is an arithmetic number, because the mean of its divisors is an integer number (3640455).

Almost surely, 2^81607140 is an apocalyptic number.

It is an amenable number.

81607140 is an abundant number, since it is smaller than the sum of its proper divisors (180505620).

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

81607140 is a wasteful number, since it uses less digits than its factorization.

81607140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26701 (or 26696 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 27.

The square root of 81607140 is about 9033.6670295069. The cubic root of 81607140 is about 433.7532274479.

Adding to 81607140 its reverse (4170618), we get a palindrome (85777758).

The spelling of 81607140 in words is "eighty-one million, six hundred seven thousand, one hundred forty".