818621 has 2 divisors, whose sum is σ = 818622. Its totient is φ = 818620.

The previous prime is 818603. The next prime is 818659. The reversal of 818621 is 126818.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 662596 + 156025 = 814^2 + 395^2 .

It is a cyclic number.

It is not a de Polignac number, because 818621 - 2¹⁸ = 556477 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (818021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 409310 + 409311.

It is an arithmetic number, because the mean of its divisors is an integer number (409311).

2⁸¹⁸⁶²¹ is an apocalyptic number.

It is an amenable number.

818621 is a deficient number, since it is larger than the sum of its proper divisors (1).

818621 is an equidigital number, since it uses as much as digits as its factorization.

818621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 768, while the sum is 26.

The square root of 818621 is about 904.7767680483. The cubic root of 818621 is about 93.5465180747.

The spelling of 818621 in words is "eight hundred eighteen thousand, six hundred twenty-one".