31187489 has 4 divisors (see below), whose sum is σ = 31212420. Its totient is φ = 31162560.

The previous prime is 31187483. The next prime is 31187491. The reversal of 31187489 is 98478113.

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 17497489 + 13690000 = 4183^2 + 3700^2 .

It is a cyclic number.

It is not a de Polignac number, because 31187489 - 2¹² = 31183393 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (31187483) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10484 + ... + 13125.

It is an arithmetic number, because the mean of its divisors is an integer number (7803105).

Almost surely, 2^31187489 is an apocalyptic number.

It is an amenable number.

31187489 is a deficient number, since it is larger than the sum of its proper divisors (24931).

31187489 is a wasteful number, since it uses less digits than its factorization.

31187489 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24930.

The product of its digits is 48384, while the sum is 41.

The square root of 31187489 is about 5584.5759910668. The cubic root of 31187489 is about 314.7700984780.

The spelling of 31187489 in words is "thirty-one million, one hundred eighty-seven thousand, four hundred eighty-nine".