30906 has 24 divisors (see below), whose sum is σ = 71604. Its totient is φ = 9600.

The previous prime is 30893. The next prime is 30911. The reversal of 30906 is 60903.

Added to its reverse (60903) it gives a square (91809 = 303²).

It can be written as a sum of positive squares in 2 ways, for example, as 25281 + 5625 = 159^2 + 75^2 .

It is a Smith number, since the sum of its digits (18) coincides with the sum of the digits of its prime factors.

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

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

30906 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, 256 + ... + 356.

2³⁰⁹⁰⁶ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 30906, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35802).

30906 is an abundant number, since it is smaller than the sum of its proper divisors (40698).

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

30906 is a wasteful number, since it uses less digits than its factorization.

30906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 126 (or 123 counting only the distinct ones).

The product of its (nonzero) digits is 162, while the sum is 18.

The square root of 30906 is about 175.8010238878. The cubic root of 30906 is about 31.3820227873.

Adding to 30906 its reverse (60903), we get a square (91809 = 303²).

The spelling of 30906 in words is "thirty thousand, nine hundred six".