31240440 has 384 divisors, whose sum is σ = 134784000. Its totient is φ = 6209280.

The previous prime is 31240439. The next prime is 31240481. The reversal of 31240440 is 4404213.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1358269 + ... + 1358291.

It is an arithmetic number, because the mean of its divisors is an integer number (351000).

Almost surely, 2^31240440 is an apocalyptic number.

31240440 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 31240440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (67392000).

31240440 is an abundant number, since it is smaller than the sum of its proper divisors (103543560).

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

31240440 is a wasteful number, since it uses less digits than its factorization.

31240440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72 (or 51 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

The square root of 31240440 is about 5589.3148059489. The cubic root of 31240440 is about 314.9481396105.

Adding to 31240440 its reverse (4404213), we get a palindrome (35644653).

It can be divided in two parts, 31 and 240440, that added together give a triangular number (240471 = T₆₉₃).

The spelling of 31240440 in words is "thirty-one million, two hundred forty thousand, four hundred forty".