31140239 has 4 divisors (see below), whose sum is σ = 33535656. Its totient is φ = 28744824.

The previous prime is 31140233. The next prime is 31140251. The reversal of 31140239 is 93204113.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93204113 = 101 ⋅922813.

It is a cyclic number.

It is not a de Polignac number, because 31140239 - 2¹² = 31136143 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 (31140233) 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, 1197689 + ... + 1197714.

It is an arithmetic number, because the mean of its divisors is an integer number (8383914).

Almost surely, 2^31140239 is an apocalyptic number.

31140239 is a deficient number, since it is larger than the sum of its proper divisors (2395417).

31140239 is a wasteful number, since it uses less digits than its factorization.

31140239 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2395416.

The product of its (nonzero) digits is 648, while the sum is 23.

The square root of 31140239 is about 5580.3439858131. The cubic root of 31140239 is about 314.6110560231.

The spelling of 31140239 in words is "thirty-one million, one hundred forty thousand, two hundred thirty-nine".