521540839 has 2 divisors, whose sum is σ = 521540840. Its totient is φ = 521540838.

The previous prime is 521540827. The next prime is 521540881. The reversal of 521540839 is 938045125.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 521540839 - 2⁷ = 521540711 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 521540798 and 521540807.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (521540819) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 260770419 + 260770420.

It is an arithmetic number, because the mean of its divisors is an integer number (260770420).

Almost surely, 2^521540839 is an apocalyptic number.

521540839 is a deficient number, since it is larger than the sum of its proper divisors (1).

521540839 is an equidigital number, since it uses as much as digits as its factorization.

521540839 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 43200, while the sum is 37.

The square root of 521540839 is about 22837.2686414116. The cubic root of 521540839 is about 804.9386365786.

The spelling of 521540839 in words is "five hundred twenty-one million, five hundred forty thousand, eight hundred thirty-nine".