518718720021 has 32 divisors (see below), whose sum is σ = 741705000960. Its totient is φ = 321673391424.

The previous prime is 518718720019. The next prime is 518718720029. The reversal of 518718720021 is 120027817815.

It is a happy number.

It is not a de Polignac number, because 518718720021 - 2¹ = 518718720019 is a prime.

It is a super-2 number, since 2×518718720021² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (518718720029) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 297720 + ... + 1061166.

It is an arithmetic number, because the mean of its divisors is an integer number (23178281280).

Almost surely, 2^518718720021 is an apocalyptic number.

It is an amenable number.

518718720021 is a deficient number, since it is larger than the sum of its proper divisors (222986280939).

518718720021 is a wasteful number, since it uses less digits than its factorization.

518718720021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 763745.

The product of its (nonzero) digits is 62720, while the sum is 42.

The spelling of 518718720021 in words is "five hundred eighteen billion, seven hundred eighteen million, seven hundred twenty thousand, twenty-one".