18021393247 has 24 divisors (see below), whose sum is σ = 21483863280. Its totient is φ = 14983937280.

The previous prime is 18021393227. The next prime is 18021393259. The reversal of 18021393247 is 74239312081.

It is not a de Polignac number, because 18021393247 - 2¹⁹ = 18020868959 is a prime.

It is a super-2 number, since 2×18021393247² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18021393217) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 158163 + ... + 247099.

It is an arithmetic number, because the mean of its divisors is an integer number (895160970).

Almost surely, 2^18021393247 is an apocalyptic number.

18021393247 is a deficient number, since it is larger than the sum of its proper divisors (3462470033).

18021393247 is a wasteful number, since it uses less digits than its factorization.

18021393247 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89083 (or 89070 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 40.

The spelling of 18021393247 in words is "eighteen billion, twenty-one million, three hundred ninety-three thousand, two hundred forty-seven".