30188921 has 4 divisors (see below), whose sum is σ = 34501632. Its totient is φ = 25876212.

The previous prime is 30188911. The next prime is 30188953. The reversal of 30188921 is 12988103.

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: 12988103 = 41 ⋅316783.

It is a cyclic number.

It is not a de Polignac number, because 30188921 - 2¹⁰ = 30187897 is a prime.

It is a super-2 number, since 2×30188921² = 1822741902288482, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (30188911) 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, 2156345 + ... + 2156358.

It is an arithmetic number, because the mean of its divisors is an integer number (8625408).

Almost surely, 2^30188921 is an apocalyptic number.

It is an amenable number.

30188921 is a deficient number, since it is larger than the sum of its proper divisors (4312711).

30188921 is an equidigital number, since it uses as much as digits as its factorization.

30188921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4312710.

The product of its (nonzero) digits is 3456, while the sum is 32.

The square root of 30188921 is about 5494.4445579148. Note that the first 3 decimals coincide. The cubic root of 30188921 is about 311.3741323014.

The spelling of 30188921 in words is "thirty million, one hundred eighty-eight thousand, nine hundred twenty-one".