501220561 has 2 divisors, whose sum is σ = 501220562. Its totient is φ = 501220560.

The previous prime is 501220547. The next prime is 501220579. The reversal of 501220561 is 165022105.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 252969025 + 248251536 = 15905^2 + 15756^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-501220561 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (501220261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 250610280 + 250610281.

It is an arithmetic number, because the mean of its divisors is an integer number (250610281).

Almost surely, 2^501220561 is an apocalyptic number.

It is an amenable number.

501220561 is a deficient number, since it is larger than the sum of its proper divisors (1).

501220561 is an equidigital number, since it uses as much as digits as its factorization.

501220561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 600, while the sum is 22.

The square root of 501220561 is about 22387.9557128381. The cubic root of 501220561 is about 794.3458411094.

Adding to 501220561 its reverse (165022105), we get a palindrome (666242666).

The spelling of 501220561 in words is "five hundred one million, two hundred twenty thousand, five hundred sixty-one".