18728993381 has 16 divisors (see below), whose sum is σ = 22669478784. Its totient is φ = 15105222144.

The previous prime is 18728993377. The next prime is 18728993401. The reversal of 18728993381 is 18339982781.

It is a cyclic number.

It is not a de Polignac number, because 18728993381 - 2² = 18728993377 is a prime.

It is a super-2 number, since 2×18728993381² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 18728993381.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18728993341) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 501161 + ... + 537233.

It is an arithmetic number, because the mean of its divisors is an integer number (1416842424).

Almost surely, 2^18728993381 is an apocalyptic number.

It is an amenable number.

18728993381 is a deficient number, since it is larger than the sum of its proper divisors (3940485403).

18728993381 is a wasteful number, since it uses less digits than its factorization.

18728993381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40460.

The product of its digits is 5225472, while the sum is 59.

The spelling of 18728993381 in words is "eighteen billion, seven hundred twenty-eight million, nine hundred ninety-three thousand, three hundred eighty-one".