18721749999 has 16 divisors (see below), whose sum is σ = 25279575552. Its totient is φ = 12322742208.

The previous prime is 18721749911. The next prime is 18721750001. The reversal of 18721749999 is 99994712781.

It is not a de Polignac number, because 18721749999 - 2¹¹ = 18721747951 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18721749899) 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, 370419 + ... + 417915.

It is an arithmetic number, because the mean of its divisors is an integer number (1579973472).

Almost surely, 2^18721749999 is an apocalyptic number.

18721749999 is a deficient number, since it is larger than the sum of its proper divisors (6557825553).

18721749999 is a wasteful number, since it uses less digits than its factorization.

18721749999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49166.

The product of its digits is 20575296, while the sum is 66.

The spelling of 18721749999 in words is "eighteen billion, seven hundred twenty-one million, seven hundred forty-nine thousand, nine hundred ninety-nine".