506561021 has 2 divisors, whose sum is σ = 506561022. Its totient is φ = 506561020.

The previous prime is 506560997. The next prime is 506561023. The reversal of 506561021 is 120165605.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 435765625 + 70795396 = 20875^2 + 8414^2 .

It is a cyclic number.

It is not a de Polignac number, because 506561021 - 2²² = 502366717 is a prime.

It is a Sophie Germain prime.

Together with 506561023, it forms a pair of twin primes.

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 (506561023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 253280510 + 253280511.

It is an arithmetic number, because the mean of its divisors is an integer number (253280511).

Almost surely, 2^506561021 is an apocalyptic number.

It is an amenable number.

506561021 is a deficient number, since it is larger than the sum of its proper divisors (1).

506561021 is an equidigital number, since it uses as much as digits as its factorization.

506561021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1800, while the sum is 26.

The square root of 506561021 is about 22506.9105165502. The cubic root of 506561021 is about 797.1571078597.

The spelling of 506561021 in words is "five hundred six million, five hundred sixty-one thousand, twenty-one".