18020381581764 has 81 divisors (see below), whose sum is σ = 46004758991373. Its totient is φ = 5947609485024.

The previous prime is 18020381581753. The next prime is 18020381581789. The reversal of 18020381581764 is 46718518302081.

The square root of 18020381581764 is 4245042.

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

18020381581764 is a `hidden beast` number, since 1 + 8 + 0 + 20 + 38 + 1 + 581 + 7 + 6 + 4 = 666.

It can be written as a sum of positive squares in only one way, i.e., 256179724164 + 17764201857600 = 506142^2 + 4214760^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 18020381581764.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 2623432522 + ... + 2623439390.

Almost surely, 2^{18020381581764} is an apocalyptic number.

18020381581764 is the 4245042-nd square number.

It is an amenable number.

18020381581764 is an abundant number, since it is smaller than the sum of its proper divisors (27984377409609).

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

18020381581764 is an frugal number, since it uses more digits than its factorization.

18020381581764 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13954 (or 6977 counting only the distinct ones).

The product of its (nonzero) digits is 2580480, while the sum is 54.

The spelling of 18020381581764 in words is "eighteen trillion, twenty billion, three hundred eighty-one million, five hundred eighty-one thousand, seven hundred sixty-four".