31140240 has 80 divisors (see below), whose sum is σ = 101630400. Its totient is φ = 7865856.

The previous prime is 31140233. The next prime is 31140251. The reversal of 31140240 is 4204113.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1146 + ... + 7974.

It is an arithmetic number, because the mean of its divisors is an integer number (1270380).

Almost surely, 2^31140240 is an apocalyptic number.

31140240 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31140240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (50815200).

31140240 is an abundant number, since it is smaller than the sum of its proper divisors (70490160).

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

31140240 is a wasteful number, since it uses less digits than its factorization.

31140240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6864 (or 6858 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 31140240 is about 5580.3440754133. The cubic root of 31140240 is about 314.6110593908.

Adding to 31140240 its reverse (4204113), we get a palindrome (35344353).

The spelling of 31140240 in words is "thirty-one million, one hundred forty thousand, two hundred forty".