31231987 has 8 divisors (see below), whose sum is σ = 31711680. Its totient is φ = 30754920.

The previous prime is 31231961. The next prime is 31232011. The reversal of 31231987 is 78913213.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 31231987 - 2⁷ = 31231859 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31261987) 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 7 ways as a sum of consecutive naturals, for example, 47064 + ... + 47722.

It is an arithmetic number, because the mean of its divisors is an integer number (3963960).

Almost surely, 2^31231987 is an apocalyptic number.

31231987 is a deficient number, since it is larger than the sum of its proper divisors (479693).

31231987 is an equidigital number, since it uses as much as digits as its factorization.

31231987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1313.

The product of its digits is 9072, while the sum is 34.

The square root of 31231987 is about 5588.5585798129. The cubic root of 31231987 is about 314.9197309541.

The spelling of 31231987 in words is "thirty-one million, two hundred thirty-one thousand, nine hundred eighty-seven".