18664209394394 has 4 divisors (see below), whose sum is σ = 27996314091594. Its totient is φ = 9332104697196.

The previous prime is 18664209394381. The next prime is 18664209394421. The reversal of 18664209394394 is 49349390246681.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 9787593591169 + 8876615803225 = 3128513^2 + 2979365^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4666052348597 + ... + 4666052348600.

Almost surely, 2^{18664209394394} is an apocalyptic number.

18664209394394 is a deficient number, since it is larger than the sum of its proper divisors (9332104697200).

18664209394394 is an equidigital number, since it uses as much as digits as its factorization.

18664209394394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9332104697199.

The product of its (nonzero) digits is 241864704, while the sum is 68.

The spelling of 18664209394394 in words is "eighteen trillion, six hundred sixty-four billion, two hundred nine million, three hundred ninety-four thousand, three hundred ninety-four".