621009217 has 2 divisors, whose sum is σ = 621009218. Its totient is φ = 621009216.

The previous prime is 621009211. The next prime is 621009253. The reversal of 621009217 is 712900126.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 407878416 + 213130801 = 20196^2 + 14599^2 .

It is a cyclic number.

It is not a de Polignac number, because 621009217 - 2³ = 621009209 is a prime.

It is not a weakly prime, because it can be changed into another prime (621009211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 310504608 + 310504609.

It is an arithmetic number, because the mean of its divisors is an integer number (310504609).

Almost surely, 2^621009217 is an apocalyptic number.

It is an amenable number.

621009217 is a deficient number, since it is larger than the sum of its proper divisors (1).

621009217 is an equidigital number, since it uses as much as digits as its factorization.

621009217 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1512, while the sum is 28.

The square root of 621009217 is about 24920.0565208027. The cubic root of 621009217 is about 853.1643148560.

It can be divided in two parts, 62100 and 9217, that added together give a palindrome (71317).

The spelling of 621009217 in words is "six hundred twenty-one million, nine thousand, two hundred seventeen".