31680745 has 4 divisors (see below), whose sum is σ = 38016900. Its totient is φ = 25344592.

The previous prime is 31680743. The next prime is 31680751. The reversal of 31680745 is 54708613.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 54708613 = 131 ⋅417623.

It can be written as a sum of positive squares in 2 ways, for example, as 9665881 + 22014864 = 3109^2 + 4692^2 .

It is a cyclic number.

It is not a de Polignac number, because 31680745 - 2¹ = 31680743 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31680745.

It is not an unprimeable number, because it can be changed into a prime (31680743) 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, 3168070 + ... + 3168079.

It is an arithmetic number, because the mean of its divisors is an integer number (9504225).

Almost surely, 2^31680745 is an apocalyptic number.

It is an amenable number.

31680745 is a deficient number, since it is larger than the sum of its proper divisors (6336155).

31680745 is an equidigital number, since it uses as much as digits as its factorization.

31680745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6336154.

The product of its (nonzero) digits is 20160, while the sum is 34.

The square root of 31680745 is about 5628.5650924547. The cubic root of 31680745 is about 316.4208760612.

The spelling of 31680745 in words is "thirty-one million, six hundred eighty thousand, seven hundred forty-five".