31878220 has 48 divisors (see below), whose sum is σ = 74608128. Its totient is φ = 11341760.

The previous prime is 31878169. The next prime is 31878229. The reversal of 31878220 is 2287813.

It is not an unprimeable number, because it can be changed into a prime (31878229) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 8799 + ... + 11881.

It is an arithmetic number, because the mean of its divisors is an integer number (1554336).

Almost surely, 2^31878220 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 31878220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37304064).

31878220 is an abundant number, since it is smaller than the sum of its proper divisors (42729908).

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

31878220 is a wasteful number, since it uses less digits than its factorization.

31878220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3150 (or 3148 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 31.

The square root of 31878220 is about 5646.0800561097. The cubic root of 31878220 is about 317.0769615470.

The spelling of 31878220 in words is "thirty-one million, eight hundred seventy-eight thousand, two hundred twenty".