78217618538 has 8 divisors (see below), whose sum is σ = 117419621760. Its totient is φ = 39077744620.

The previous prime is 78217618517. The next prime is 78217618561. The reversal of 78217618538 is 83581671287.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×78217618538² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15529178 + ... + 15534213.

It is an arithmetic number, because the mean of its divisors is an integer number (14677452720).

Almost surely, 2^78217618538 is an apocalyptic number.

78217618538 is a deficient number, since it is larger than the sum of its proper divisors (39202003222).

78217618538 is a wasteful number, since it uses less digits than its factorization.

78217618538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31064652.

The product of its digits is 4515840, while the sum is 56.

The spelling of 78217618538 in words is "seventy-eight billion, two hundred seventeen million, six hundred eighteen thousand, five hundred thirty-eight".