518121021 has 16 divisors (see below), whose sum is σ = 756364608. Its totient is φ = 312873600.

The previous prime is 518121001. The next prime is 518121083. The reversal of 518121021 is 120121815.

It is not a de Polignac number, because 518121021 - 2¹⁴ = 518104637 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (518121001) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19200 + ... + 37481.

It is an arithmetic number, because the mean of its divisors is an integer number (47272788).

Almost surely, 2^518121021 is an apocalyptic number.

It is an amenable number.

518121021 is a deficient number, since it is larger than the sum of its proper divisors (238243587).

518121021 is a wasteful number, since it uses less digits than its factorization.

518121021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56972.

The product of its (nonzero) digits is 160, while the sum is 21.

The square root of 518121021 is about 22762.2718769459. The cubic root of 518121021 is about 803.1754110504.

Adding to 518121021 its reverse (120121815), we get a palindrome (638242836).

It can be divided in two parts, 5181 and 21021, that multiplied together give a palindrome (108909801).

The spelling of 518121021 in words is "five hundred eighteen million, one hundred twenty-one thousand, twenty-one".