621620213 has 2 divisors, whose sum is σ = 621620214. Its totient is φ = 621620212.

The previous prime is 621620203. The next prime is 621620221. The reversal of 621620213 is 312026126.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 523174129 + 98446084 = 22873^2 + 9922^2 .

It is a cyclic number.

It is not a de Polignac number, because 621620213 - 2¹⁶ = 621554677 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (621620203) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 310810106 + 310810107.

It is an arithmetic number, because the mean of its divisors is an integer number (310810107).

Almost surely, 2^621620213 is an apocalyptic number.

It is an amenable number.

621620213 is a deficient number, since it is larger than the sum of its proper divisors (1).

621620213 is an equidigital number, since it uses as much as digits as its factorization.

621620213 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 621620213 is about 24932.3126283945. The cubic root of 621620213 is about 853.4440257441. Note that the first 3 decimals are identical.

Adding to 621620213 its reverse (312026126), we get a palindrome (933646339).

The spelling of 621620213 in words is "six hundred twenty-one million, six hundred twenty thousand, two hundred thirteen".