521539961 has 2 divisors, whose sum is σ = 521539962. Its totient is φ = 521539960.

The previous prime is 521539937. The next prime is 521540003. The reversal of 521539961 is 169935125.

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., 497959225 + 23580736 = 22315^2 + 4856^2 .

It is a cyclic number.

It is not a de Polignac number, because 521539961 - 2⁶ = 521539897 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (521539661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 260769980 + 260769981.

It is an arithmetic number, because the mean of its divisors is an integer number (260769981).

Almost surely, 2^521539961 is an apocalyptic number.

It is an amenable number.

521539961 is a deficient number, since it is larger than the sum of its proper divisors (1).

521539961 is an equidigital number, since it uses as much as digits as its factorization.

521539961 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72900, while the sum is 41.

The square root of 521539961 is about 22837.2494184392. The cubic root of 521539961 is about 804.9381848809.

The spelling of 521539961 in words is "five hundred twenty-one million, five hundred thirty-nine thousand, nine hundred sixty-one".