18537321919 has 4 divisors (see below), whose sum is σ = 18590743944. Its totient is φ = 18483899896.

The previous prime is 18537321889. The next prime is 18537321967. The reversal of 18537321919 is 91912373581.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 18537321919 - 2¹³ = 18537313727 is a prime.

It is a super-2 number, since 2×18537321919² (a number of 21 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18537321989) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26710492 + ... + 26711185.

It is an arithmetic number, because the mean of its divisors is an integer number (4647685986).

Almost surely, 2^18537321919 is an apocalyptic number.

18537321919 is a deficient number, since it is larger than the sum of its proper divisors (53422025).

18537321919 is an equidigital number, since it uses as much as digits as its factorization.

18537321919 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53422024.

The product of its digits is 408240, while the sum is 49.

The spelling of 18537321919 in words is "eighteen billion, five hundred thirty-seven million, three hundred twenty-one thousand, nine hundred nineteen".