17994638506 has 16 divisors (see below), whose sum is σ = 29090867400. Its totient is φ = 8298759168.

The previous prime is 17994638491. The next prime is 17994638513. The reversal of 17994638506 is 60583649971.

It can be written as a sum of positive squares in 4 ways, for example, as 15147455625 + 2847182881 = 123075^2 + 53359^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 234951 + ... + 301978.

Almost surely, 2^17994638506 is an apocalyptic number.

17994638506 is a deficient number, since it is larger than the sum of its proper divisors (11096228894).

17994638506 is a wasteful number, since it uses less digits than its factorization.

17994638506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 538233.

The product of its (nonzero) digits is 9797760, while the sum is 58.

The spelling of 17994638506 in words is "seventeen billion, nine hundred ninety-four million, six hundred thirty-eight thousand, five hundred six".