30921 has 8 divisors (see below), whose sum is σ = 45024. Its totient is φ = 18720.

The previous prime is 30911. The next prime is 30931. The reversal of 30921 is 12903.

30921 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (30911) and next prime (30931).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 30921 - 2¹⁴ = 14537 is a prime.

It is a super-2 number, since 2×30921² = 1912216482, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is a Curzon number.

It is a nialpdrome in base 8.

It is a self number, because there is not a number n which added to its sum of digits gives 30921.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 30921.

It is not an unprimeable number, because it can be changed into a prime (30911) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 436 + ... + 501.

It is an arithmetic number, because the mean of its divisors is an integer number (5628).

2³⁰⁹²¹ is an apocalyptic number.

It is an amenable number.

30921 is a deficient number, since it is larger than the sum of its proper divisors (14103).

30921 is a wasteful number, since it uses less digits than its factorization.

30921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 951.

The product of its (nonzero) digits is 54, while the sum is 15.

The square root of 30921 is about 175.8436805802. The cubic root of 30921 is about 31.3870989776.

The spelling of 30921 in words is "thirty thousand, nine hundred twenty-one".