133731 has 20 divisors (see below), whose sum is σ = 216832. Its totient is φ = 81648.

The previous prime is 133723. The next prime is 133733. The reversal of 133731 is 137331.

It is not a de Polignac number, because 133731 - 2³ = 133723 is a prime.

It is a super-2 number, since 2×133731² = 35767960722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (133733) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 990 + ... + 1116.

2¹³³⁷³¹ is an apocalyptic number.

133731 is a deficient number, since it is larger than the sum of its proper divisors (83101).

133731 is a wasteful number, since it uses less digits than its factorization.

133731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 152 (or 143 counting only the distinct ones).

The product of its digits is 189, while the sum is 18.

The square root of 133731 is about 365.6924937704. The cubic root of 133731 is about 51.1380343697.

Subtracting 133731 from its reverse (137331), we obtain a square (3600 = 60²).

The spelling of 133731 in words is "one hundred thirty-three thousand, seven hundred thirty-one".