31225440 has 48 divisors (see below), whose sum is σ = 98361648. Its totient is φ = 8326656.

The previous prime is 31225429. The next prime is 31225457. The reversal of 31225440 is 4452213.

It is a tau number, because it is divible by the number of its divisors (48).

It is a congruent number.

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, 32047 + ... + 33006.

It is an arithmetic number, because the mean of its divisors is an integer number (2049201).

Almost surely, 2^31225440 is an apocalyptic number.

31225440 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

31225440 is an abundant number, since it is smaller than the sum of its proper divisors (67136208).

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

31225440 is a wasteful number, since it uses less digits than its factorization.

31225440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65071 (or 65063 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 21.

The square root of 31225440 is about 5587.9727987885. The cubic root of 31225440 is about 314.8977244179.

Adding to 31225440 its reverse (4452213), we get a palindrome (35677653).

It can be divided in two parts, 312 and 25440, that added together give a palindrome (25752).

The spelling of 31225440 in words is "thirty-one million, two hundred twenty-five thousand, four hundred forty".