31393661 has 4 divisors (see below), whose sum is σ = 33808572. Its totient is φ = 28978752.

The previous prime is 31393651. The next prime is 31393667. The reversal of 31393661 is 16639313.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 16639313 = 173 ⋅96181.

It can be written as a sum of positive squares in 2 ways, for example, as 13912900 + 17480761 = 3730^2 + 4181^2 .

It is a cyclic number.

It is not a de Polignac number, because 31393661 - 2¹⁰ = 31392637 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 (31393667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1207436 + ... + 1207461.

It is an arithmetic number, because the mean of its divisors is an integer number (8452143).

Almost surely, 2^31393661 is an apocalyptic number.

It is an amenable number.

31393661 is a deficient number, since it is larger than the sum of its proper divisors (2414911).

31393661 is a wasteful number, since it uses less digits than its factorization.

31393661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2414910.

The product of its digits is 8748, while the sum is 32.

The square root of 31393661 is about 5603.0046403693. The cubic root of 31393661 is about 315.4621954346.

The spelling of 31393661 in words is "thirty-one million, three hundred ninety-three thousand, six hundred sixty-one".