31872 has 32 divisors (see below), whose sum is σ = 85680. Its totient is φ = 10496.

The previous prime is 31859. The next prime is 31873. The reversal of 31872 is 27813.

Added to its reverse (27813) it gives a triangular number (59685 = T₃₄₅).

It is a tau number, because it is divible by the number of its divisors (32).

It is a plaindrome in base 13.

It is a nialpdrome in base 8 and base 14.

It is not an unprimeable number, because it can be changed into a prime (31873) by changing a digit.

31872 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 343 + ... + 425.

2³¹⁸⁷² is an apocalyptic number.

31872 is a gapful number since it is divisible by the number (32) 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 31872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42840).

31872 is an abundant number, since it is smaller than the sum of its proper divisors (53808).

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

31872 is an equidigital number, since it uses as much as digits as its factorization.

31872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100 (or 88 counting only the distinct ones).

The product of its digits is 336, while the sum is 21.

The square root of 31872 is about 178.5273088354. The cubic root of 31872 is about 31.7056337780.

Adding to 31872 its reverse (27813), we get a triangular number (59685 = T₃₄₅).

It can be divided in two parts, 31 and 872, that added together give a triangular number (903 = T₄₂).

The spelling of 31872 in words is "thirty-one thousand, eight hundred seventy-two".