521440247 has 2 divisors, whose sum is σ = 521440248. Its totient is φ = 521440246.

The previous prime is 521440219. The next prime is 521440307. The reversal of 521440247 is 742044125.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 521440247 - 2¹⁰ = 521439223 is a prime.

It is equal to p_27424190 and since 521440247 and 27424190 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (521440147) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 260720123 + 260720124.

It is an arithmetic number, because the mean of its divisors is an integer number (260720124).

Almost surely, 2^521440247 is an apocalyptic number.

521440247 is a deficient number, since it is larger than the sum of its proper divisors (1).

521440247 is an equidigital number, since it uses as much as digits as its factorization.

521440247 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8960, while the sum is 29.

The square root of 521440247 is about 22835.0661702567. The cubic root of 521440247 is about 804.8868825020.

The spelling of 521440247 in words is "five hundred twenty-one million, four hundred forty thousand, two hundred forty-seven".