306399021 has 4 divisors (see below), whose sum is σ = 408532032. Its totient is φ = 204266012.

The previous prime is 306399019. The next prime is 306399029. The reversal of 306399021 is 120993603.

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: 120993603 = 3 ⋅40331201.

It is a cyclic number.

It is not a de Polignac number, because 306399021 - 2¹ = 306399019 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (306399029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 51066501 + ... + 51066506.

It is an arithmetic number, because the mean of its divisors is an integer number (102133008).

Almost surely, 2^306399021 is an apocalyptic number.

It is an amenable number.

306399021 is a deficient number, since it is larger than the sum of its proper divisors (102133011).

306399021 is a wasteful number, since it uses less digits than its factorization.

306399021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102133010.

The product of its (nonzero) digits is 8748, while the sum is 33.

The square root of 306399021 is about 17504.2572250296. The cubic root of 306399021 is about 674.1591879216.

The spelling of 306399021 in words is "three hundred six million, three hundred ninety-nine thousand, twenty-one".