518352721921 has 2 divisors, whose sum is σ = 518352721922. Its totient is φ = 518352721920.

The previous prime is 518352721919. The next prime is 518352721967. The reversal of 518352721921 is 129127253815.

It is an a-pointer prime, because the next prime (518352721967) can be obtained adding 518352721921 to its sum of digits (46).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 518343841521 + 8880400 = 719961^2 + 2980^2 .

It is a cyclic number.

It is not a de Polignac number, because 518352721921 - 2¹ = 518352721919 is a prime.

Together with 518352721919, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (518352721981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 259176360960 + 259176360961.

It is an arithmetic number, because the mean of its divisors is an integer number (259176360961).

Almost surely, 2^518352721921 is an apocalyptic number.

It is an amenable number.

518352721921 is a deficient number, since it is larger than the sum of its proper divisors (1).

518352721921 is an equidigital number, since it uses as much as digits as its factorization.

518352721921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 302400, while the sum is 46.

The spelling of 518352721921 in words is "five hundred eighteen billion, three hundred fifty-two million, seven hundred twenty-one thousand, nine hundred twenty-one".