520761821 has 2 divisors, whose sum is σ = 520761822. Its totient is φ = 520761820.

The previous prime is 520761809. The next prime is 520761847. The reversal of 520761821 is 128167025.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 295461721 + 225300100 = 17189^2 + 15010^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-520761821 is a prime.

It is a super-2 number, since 2×520761821² = 542385748422472082, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (520761881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 260380910 + 260380911.

It is an arithmetic number, because the mean of its divisors is an integer number (260380911).

Almost surely, 2^520761821 is an apocalyptic number.

It is an amenable number.

520761821 is a deficient number, since it is larger than the sum of its proper divisors (1).

520761821 is an equidigital number, since it uses as much as digits as its factorization.

520761821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6720, while the sum is 32.

The square root of 520761821 is about 22820.2064188736. The cubic root of 520761821 is about 804.5376618066.

The spelling of 520761821 in words is "five hundred twenty million, seven hundred sixty-one thousand, eight hundred twenty-one".