31242440 has 32 divisors (see below), whose sum is σ = 71626680. Its totient is φ = 12260352.

The previous prime is 31242433. The next prime is 31242457. The reversal of 31242440 is 4424213.

It can be written as a sum of positive squares in 4 ways, for example, as 30492484 + 749956 = 5522^2 + 866^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 5249 + ... + 9488.

Almost surely, 2^31242440 is an apocalyptic number.

It is an amenable number.

31242440 is an abundant number, since it is smaller than the sum of its proper divisors (40384240).

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

31242440 is a wasteful number, since it uses less digits than its factorization.

31242440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14801 (or 14797 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 20.

The square root of 31242440 is about 5589.4937158923. The cubic root of 31242440 is about 314.9548604168.

Adding to 31242440 its reverse (4424213), we get a palindrome (35666653).

It can be divided in two parts, 3124 and 2440, that multiplied together give a triangular number (7622560 = T₃₉₀₄).

The spelling of 31242440 in words is "thirty-one million, two hundred forty-two thousand, four hundred forty".