309601021 has 4 divisors (see below), whose sum is σ = 309638844. Its totient is φ = 309563200.

The previous prime is 309601009. The next prime is 309601049. The reversal of 309601021 is 120106903.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 120106903 = 7 ⋅17158129.

It can be written as a sum of positive squares in 2 ways, for example, as 209380900 + 100220121 = 14470^2 + 10011^2 .

It is a cyclic number.

It is not a de Polignac number, because 309601021 - 2⁹ = 309600509 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 309600983 and 309601001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (309601001) 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, 940 + ... + 24901.

It is an arithmetic number, because the mean of its divisors is an integer number (77409711).

Almost surely, 2^309601021 is an apocalyptic number.

It is an amenable number.

309601021 is a deficient number, since it is larger than the sum of its proper divisors (37823).

309601021 is a wasteful number, since it uses less digits than its factorization.

309601021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37822.

The product of its (nonzero) digits is 324, while the sum is 22.

The square root of 309601021 is about 17595.4829714902. The cubic root of 309601021 is about 676.4994711228.

Adding to 309601021 its reverse (120106903), we get a palindrome (429707924).

The spelling of 309601021 in words is "three hundred nine million, six hundred one thousand, twenty-one".