623561221 has 2 divisors, whose sum is σ = 623561222. Its totient is φ = 623561220.

The previous prime is 623561201. The next prime is 623561243. The reversal of 623561221 is 122165326.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 575328196 + 48233025 = 23986^2 + 6945^2 .

It is a cyclic number.

It is not a de Polignac number, because 623561221 - 2⁹ = 623560709 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 623561221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (623561201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 311780610 + 311780611.

It is an arithmetic number, because the mean of its divisors is an integer number (311780611).

Almost surely, 2^623561221 is an apocalyptic number.

It is an amenable number.

623561221 is a deficient number, since it is larger than the sum of its proper divisors (1).

623561221 is an equidigital number, since it uses as much as digits as its factorization.

623561221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4320, while the sum is 28.

The square root of 623561221 is about 24971.2078402307. The cubic root of 623561221 is about 854.3313952606.

The spelling of 623561221 in words is "six hundred twenty-three million, five hundred sixty-one thousand, two hundred twenty-one".