31243609 has 4 divisors (see below), whose sum is σ = 31402404. Its totient is φ = 31084816.

The previous prime is 31243601. The next prime is 31243633. The reversal of 31243609 is 90634213.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14227984 + 17015625 = 3772^2 + 4125^2 .

It is a cyclic number.

It is not a de Polignac number, because 31243609 - 2³ = 31243601 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31243601) 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, 79102 + ... + 79495.

It is an arithmetic number, because the mean of its divisors is an integer number (7850601).

Almost surely, 2^31243609 is an apocalyptic number.

It is an amenable number.

31243609 is a deficient number, since it is larger than the sum of its proper divisors (158795).

31243609 is a wasteful number, since it uses less digits than its factorization.

31243609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 158794.

The product of its (nonzero) digits is 3888, while the sum is 28.

The square root of 31243609 is about 5589.5982861025. The cubic root of 31243609 is about 314.9587885953.

The spelling of 31243609 in words is "thirty-one million, two hundred forty-three thousand, six hundred nine".