31728080 has 20 divisors (see below), whose sum is σ = 73767972. Its totient is φ = 12691200.

The previous prime is 31728077. The next prime is 31728089. The reversal of 31728080 is 8082713.

It can be written as a sum of positive squares in 2 ways, for example, as 21641104 + 10086976 = 4652^2 + 3176^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31728089) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 198221 + ... + 198380.

Almost surely, 2^31728080 is an apocalyptic number.

It is an amenable number.

31728080 is an abundant number, since it is smaller than the sum of its proper divisors (42039892).

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

31728080 is a wasteful number, since it uses less digits than its factorization.

31728080 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 396614 (or 396608 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 29.

The square root of 31728080 is about 5632.7684134891. The cubic root of 31728080 is about 316.5783884428.

The spelling of 31728080 in words is "thirty-one million, seven hundred twenty-eight thousand, eighty".