30681 has 12 divisors (see below), whose sum is σ = 50752. Its totient is φ = 17496.

The previous prime is 30677. The next prime is 30689. The reversal of 30681 is 18603.

Added to its reverse (18603) it gives a square (49284 = 222²).

It is not a de Polignac number, because 30681 - 2² = 30677 is a prime.

It is a super-2 number, since 2×30681² = 1882647522, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is a Curzon number.

30681 is a lucky number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 30681.

It is not an unprimeable number, because it can be changed into a prime (30689) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 181 + ... + 306.

2³⁰⁶⁸¹ is an apocalyptic number.

It is an amenable number.

30681 is a deficient number, since it is larger than the sum of its proper divisors (20071).

30681 is a wasteful number, since it uses less digits than its factorization.

30681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 500 (or 497 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 30681 is about 175.1599269239. The cubic root of 30681 is about 31.3056820587.

Adding to 30681 its reverse (18603), we get a square (49284 = 222²).

The spelling of 30681 in words is "thirty thousand, six hundred eighty-one".