18021343655 has 16 divisors (see below), whose sum is σ = 24717843264. Its totient is φ = 12356064000.

The previous prime is 18021343619. The next prime is 18021343661. The reversal of 18021343655 is 55634312081.

It is a happy number.

It is not a de Polignac number, because 18021343655 - 2⁶ = 18021343591 is a prime.

It is a Smith number, since the sum of its digits (38) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 343019 + ... + 392051.

It is an arithmetic number, because the mean of its divisors is an integer number (1544865204).

Almost surely, 2^18021343655 is an apocalyptic number.

18021343655 is a deficient number, since it is larger than the sum of its proper divisors (6696499609).

18021343655 is a wasteful number, since it uses less digits than its factorization.

18021343655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59546.

The product of its (nonzero) digits is 86400, while the sum is 38.

The spelling of 18021343655 in words is "eighteen billion, twenty-one million, three hundred forty-three thousand, six hundred fifty-five".