18989749993 has 16 divisors (see below), whose sum is σ = 19319829696. Its totient is φ = 18663004480.

The previous prime is 18989749979. The next prime is 18989750033. The reversal of 18989749993 is 39994798981.

It is a happy number.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18989749993 is a prime.

It is a super-2 number, since 2×18989749993² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18909749993) 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, 12086898 + ... + 12088468.

It is an arithmetic number, because the mean of its divisors is an integer number (1207489356).

Almost surely, 2^18989749993 is an apocalyptic number.

It is an amenable number.

18989749993 is a deficient number, since it is larger than the sum of its proper divisors (330079703).

18989749993 is a wasteful number, since it uses less digits than its factorization.

18989749993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2504.

The product of its digits is 317447424, while the sum is 76.

The spelling of 18989749993 in words is "eighteen billion, nine hundred eighty-nine million, seven hundred forty-nine thousand, nine hundred ninety-three".