30809021 has 4 divisors (see below), whose sum is σ = 30895200. Its totient is φ = 30722844.

The previous prime is 30809003. The next prime is 30809039. The reversal of 30809021 is 12090803.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12090803 = 71 ⋅170293.

It is an interprime number because it is at equal distance from previous prime (30809003) and next prime (30809039).

It is a cyclic number.

It is not a de Polignac number, because 30809021 - 2¹⁴ = 30792637 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (30809221) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42551 + ... + 43268.

It is an arithmetic number, because the mean of its divisors is an integer number (7723800).

Almost surely, 2^30809021 is an apocalyptic number.

It is an amenable number.

30809021 is a deficient number, since it is larger than the sum of its proper divisors (86179).

30809021 is an equidigital number, since it uses as much as digits as its factorization.

30809021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86178.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 30809021 is about 5550.5874463880. The cubic root of 30809021 is about 313.4916416216.

Adding to 30809021 its reverse (12090803), we get a palindrome (42899824).

The spelling of 30809021 in words is "thirty million, eight hundred nine thousand, twenty-one".