521423284721 has 4 divisors (see below), whose sum is σ = 521645074944. Its totient is φ = 521201494500.

The previous prime is 521423284717. The next prime is 521423284741. The reversal of 521423284721 is 127482324125.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 521423284721 - 2² = 521423284717 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (521423284741) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 110891585 + ... + 110896286.

It is an arithmetic number, because the mean of its divisors is an integer number (130411268736).

Almost surely, 2^521423284721 is an apocalyptic number.

It is an amenable number.

521423284721 is a deficient number, since it is larger than the sum of its proper divisors (221790223).

521423284721 is a wasteful number, since it uses less digits than its factorization.

521423284721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 221790222.

The product of its digits is 215040, while the sum is 41.

The spelling of 521423284721 in words is "five hundred twenty-one billion, four hundred twenty-three million, two hundred eighty-four thousand, seven hundred twenty-one".