305021 has 2 divisors, whose sum is σ = 305022. Its totient is φ = 305020.

The previous prime is 305017. The next prime is 305023. The reversal of 305021 is 120503.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 156025 + 148996 = 395^2 + 386^2 .

It is an emirp because it is prime and its reverse (120503) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 305021 - 2² = 305017 is a prime.

Together with 305023, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 304993 and 305011.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (305023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 152510 + 152511.

It is an arithmetic number, because the mean of its divisors is an integer number (152511).

2³⁰⁵⁰²¹ is an apocalyptic number.

It is an amenable number.

305021 is a deficient number, since it is larger than the sum of its proper divisors (1).

305021 is an equidigital number, since it uses as much as digits as its factorization.

305021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 30, while the sum is 11.

The square root of 305021 is about 552.2870630388. The cubic root of 305021 is about 67.3146998293.

Adding to 305021 its reverse (120503), we get a palindrome (425524).

It can be divided in two parts, 30502 and 1, that added together give a palindrome (30503).

The spelling of 305021 in words is "three hundred five thousand, twenty-one".