305621 has 2 divisors, whose sum is σ = 305622. Its totient is φ = 305620.

The previous prime is 305611. The next prime is 305633. The reversal of 305621 is 126503.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 207025 + 98596 = 455^2 + 314^2 .

It is a cyclic number.

It is not a de Polignac number, because 305621 - 2¹⁰ = 304597 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 305621.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 305621.

It is not a weakly prime, because it can be changed into another prime (305611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 152810 + 152811.

It is an arithmetic number, because the mean of its divisors is an integer number (152811).

2³⁰⁵⁶²¹ is an apocalyptic number.

305621 is the 296-th centered heptagonal number.

It is an amenable number.

305621 is a deficient number, since it is larger than the sum of its proper divisors (1).

305621 is an equidigital number, since it uses as much as digits as its factorization.

305621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 180, while the sum is 17.

The square root of 305621 is about 552.8299919505. The cubic root of 305621 is about 67.3588086679.

The spelling of 305621 in words is "three hundred five thousand, six hundred twenty-one".