31438540 has 96 divisors (see below), whose sum is σ = 81285120. Its totient is φ = 9974016.

The previous prime is 31438529. The next prime is 31438571. The reversal of 31438540 is 4583413.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a junction number, because it is equal to n+sod(n) for n = 31438499 and 31438508.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 140869 + ... + 141091.

It is an arithmetic number, because the mean of its divisors is an integer number (846720).

Almost surely, 2^31438540 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 31438540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40642560).

31438540 is an abundant number, since it is smaller than the sum of its proper divisors (49846580).

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

31438540 is a wasteful number, since it uses less digits than its factorization.

31438540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 311 (or 309 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 28.

The square root of 31438540 is about 5607.0081148506. The cubic root of 31438540 is about 315.6124474961.

The spelling of 31438540 in words is "thirty-one million, four hundred thirty-eight thousand, five hundred forty".