521985647 has 2 divisors, whose sum is σ = 521985648. Its totient is φ = 521985646.

The previous prime is 521985599. The next prime is 521985649. The reversal of 521985647 is 746589125.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 521985647 - 2²⁰ = 520937071 is a prime.

Together with 521985649, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (521985649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 260992823 + 260992824.

It is an arithmetic number, because the mean of its divisors is an integer number (260992824).

Almost surely, 2^521985647 is an apocalyptic number.

521985647 is a deficient number, since it is larger than the sum of its proper divisors (1).

521985647 is an equidigital number, since it uses as much as digits as its factorization.

521985647 is an evil number, because the sum of its binary digits is even.

The product of its digits is 604800, while the sum is 47.

The square root of 521985647 is about 22847.0052085607. The cubic root of 521985647 is about 805.1674083117.

The spelling of 521985647 in words is "five hundred twenty-one million, nine hundred eighty-five thousand, six hundred forty-seven".