31356 has 36 divisors (see below), whose sum is σ = 86632. Its totient is φ = 9504.

The previous prime is 31337. The next prime is 31357. The reversal of 31356 is 65313.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (18).

Its product of digits (270) is a multiple of the sum of its prime factors (90).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31357) by changing a digit.

31356 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, 435 + ... + 501.

2³¹³⁵⁶ is an apocalyptic number.

31356 is a gapful number since it is divisible by the number (36) 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 31356, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43316).

31356 is an abundant number, since it is smaller than the sum of its proper divisors (55276).

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

31356 is a wasteful number, since it uses less digits than its factorization.

31356 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90 (or 85 counting only the distinct ones).

The product of its digits is 270, while the sum is 18.

The square root of 31356 is about 177.0762547605. The cubic root of 31356 is about 31.5335998241.

Adding to 31356 its product of digits (270), we get a triangular number (31626 = T₂₅₁).

Adding to 31356 its reverse (65313), we get a palindrome (96669).

The spelling of 31356 in words is "thirty-one thousand, three hundred fifty-six".