18639894784 has 243 divisors, whose sum is σ = 46115002353. Its totient is φ = 7497025536.

The previous prime is 18639894751. The next prime is 18639894841. The reversal of 18639894784 is 48749893681.

The square root of 18639894784 is 136528.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 13437446400 + 5202448384 = 115920^2 + 72128^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 351696102 + ... + 351696154.

Almost surely, 2^18639894784 is an apocalyptic number.

18639894784 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

18639894784 is the 136528-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18639894784

18639894784 is an abundant number, since it is smaller than the sum of its proper divisors (27475107569).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18639894784 is an frugal number, since it uses more digits than its factorization.

18639894784 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 182 (or 85 counting only the distinct ones).

The product of its digits is 83607552, while the sum is 67.

It can be divided in two parts, 186398 and 94784, that added together give a palindrome (281182).

The spelling of 18639894784 in words is "eighteen billion, six hundred thirty-nine million, eight hundred ninety-four thousand, seven hundred eighty-four".