518121647 has 4 divisors (see below), whose sum is σ = 520289760. Its totient is φ = 515953536.

The previous prime is 518121613. The next prime is 518121649. The reversal of 518121647 is 746121815.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 746121815 = 5 ⋅149224363.

It is a cyclic number.

It is not a de Polignac number, because 518121647 - 2¹⁶ = 518056111 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (518121649) 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, 1083698 + ... + 1084175.

It is an arithmetic number, because the mean of its divisors is an integer number (130072440).

Almost surely, 2^518121647 is an apocalyptic number.

518121647 is a deficient number, since it is larger than the sum of its proper divisors (2168113).

518121647 is a wasteful number, since it uses less digits than its factorization.

518121647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2168112.

The product of its digits is 13440, while the sum is 35.

The square root of 518121647 is about 22762.2856277659. The cubic root of 518121647 is about 803.1757345190.

The spelling of 518121647 in words is "five hundred eighteen million, one hundred twenty-one thousand, six hundred forty-seven".