18733973981 has 6 divisors (see below), whose sum is σ = 18861387450. Its totient is φ = 18606583088.

The previous prime is 18733973957. The next prime is 18733974011. The reversal of 18733973981 is 18937933781.

It can be written as a sum of positive squares in 3 ways, for example, as 2977448356 + 15756525625 = 54566^2 + 125525^2 .

It is a de Polignac number, because none of the positive numbers 2^k-18733973981 is a prime.

It is a super-2 number, since 2×18733973981² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18733973981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18733973081) by changing a digit.

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 5 ways as a sum of consecutive naturals, for example, 1665131 + ... + 1676343.

It is an arithmetic number, because the mean of its divisors is an integer number (3143564575).

Almost surely, 2^18733973981 is an apocalyptic number.

It is an amenable number.

18733973981 is a deficient number, since it is larger than the sum of its proper divisors (127413469).

18733973981 is an frugal number, since it uses more digits than its factorization.

18733973981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22575 (or 11362 counting only the distinct ones).

The product of its digits is 6858432, while the sum is 59.

The spelling of 18733973981 in words is "eighteen billion, seven hundred thirty-three million, nine hundred seventy-three thousand, nine hundred eighty-one".