31287144 has 128 divisors (see below), whose sum is σ = 94279680. Its totient is φ = 8467200.

The previous prime is 31287127. The next prime is 31287161. The reversal of 31287144 is 44178213.

It is an interprime number because it is at equal distance from previous prime (31287127) and next prime (31287161).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 440629 + ... + 440699.

It is an arithmetic number, because the mean of its divisors is an integer number (736560).

Almost surely, 2^31287144 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31287144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47139840).

31287144 is an abundant number, since it is smaller than the sum of its proper divisors (62992536).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31287144 is a wasteful number, since it uses less digits than its factorization.

31287144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 191 (or 187 counting only the distinct ones).

The product of its digits is 5376, while the sum is 30.

The square root of 31287144 is about 5593.4912174777. The cubic root of 31287144 is about 315.1050090818.

The spelling of 31287144 in words is "thirty-one million, two hundred eighty-seven thousand, one hundred forty-four".