31680309 has 4 divisors (see below), whose sum is σ = 42240416. Its totient is φ = 21120204.

The previous prime is 31680307. The next prime is 31680317. The reversal of 31680309 is 90308613.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 31680309 - 2¹ = 31680307 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31680301) 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, 5280049 + ... + 5280054.

It is an arithmetic number, because the mean of its divisors is an integer number (10560104).

Almost surely, 2^31680309 is an apocalyptic number.

It is an amenable number.

31680309 is a deficient number, since it is larger than the sum of its proper divisors (10560107).

31680309 is a wasteful number, since it uses less digits than its factorization.

31680309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10560106.

The product of its (nonzero) digits is 3888, while the sum is 30.

The square root of 31680309 is about 5628.5263613134. The cubic root of 31680309 is about 316.4194244946.

The spelling of 31680309 in words is "thirty-one million, six hundred eighty thousand, three hundred nine".