18980721893 has 16 divisors (see below), whose sum is σ = 21854738304. Its totient is φ = 16147783680.

The previous prime is 18980721889. The next prime is 18980721899. The reversal of 18980721893 is 39812708981.

It is not a de Polignac number, because 18980721893 - 2² = 18980721889 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18980721899) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 486746 + ... + 524292.

It is an arithmetic number, because the mean of its divisors is an integer number (1365921144).

Almost surely, 2^18980721893 is an apocalyptic number.

It is an amenable number.

18980721893 is a deficient number, since it is larger than the sum of its proper divisors (2874016411).

18980721893 is a wasteful number, since it uses less digits than its factorization.

18980721893 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38092.

The product of its (nonzero) digits is 1741824, while the sum is 56.

The spelling of 18980721893 in words is "eighteen billion, nine hundred eighty million, seven hundred twenty-one thousand, eight hundred ninety-three".