31740 has 36 divisors (see below), whose sum is σ = 92904. Its totient is φ = 8096.

The previous prime is 31729. The next prime is 31741. The reversal of 31740 is 4713.

It is a hoax number, since the sum of its digits (15) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a nialpdrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31741) by changing a digit.

31740 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 11 ways as a sum of consecutive naturals, for example, 1369 + ... + 1391.

2³¹⁷⁴⁰ is an apocalyptic number.

31740 is a gapful number since it is divisible by the number (30) 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 31740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46452).

31740 is an abundant number, since it is smaller than the sum of its proper divisors (61164).

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

31740 is a wasteful number, since it uses less digits than its factorization.

31740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58 (or 33 counting only the distinct ones).

The product of its (nonzero) digits is 84, while the sum is 15.

The square root of 31740 is about 178.1572339255. The cubic root of 31740 is about 31.6618028849.

Multiplying 31740 by its sum of digits (15), we get a square (476100 = 690²).

31740 divided by its sum of digits (15) gives a square (2116 = 46²).

The spelling of 31740 in words is "thirty-one thousand, seven hundred forty".