31686745 has 8 divisors (see below), whose sum is σ = 38545416. Its totient is φ = 25001856.

The previous prime is 31686719. The next prime is 31686749. The reversal of 31686745 is 54768613.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 6405961 + 25280784 = 2531^2 + 5028^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 31686745 - 2⁵ = 31686713 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31686698 and 31686707.

It is not an unprimeable number, because it can be changed into a prime (31686749) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 43042 + ... + 43771.

It is an arithmetic number, because the mean of its divisors is an integer number (4818177).

Almost surely, 2^31686745 is an apocalyptic number.

It is an amenable number.

31686745 is a deficient number, since it is larger than the sum of its proper divisors (6858671).

31686745 is an equidigital number, since it uses as much as digits as its factorization.

31686745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86891.

The product of its digits is 120960, while the sum is 40.

The square root of 31686745 is about 5629.0980627450. The cubic root of 31686745 is about 316.4408503959.

The spelling of 31686745 in words is "thirty-one million, six hundred eighty-six thousand, seven hundred forty-five".