18913173137 has 4 divisors (see below), whose sum is σ = 18913453860. Its totient is φ = 18912892416.

The previous prime is 18913173101. The next prime is 18913173143. The reversal of 18913173137 is 73137131981.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 73137131981 = 269 ⋅271885249.

It can be written as a sum of positive squares in 2 ways, for example, as 11569368721 + 7343804416 = 107561^2 + 85696^2 .

It is a cyclic number.

It is not a de Polignac number, because 18913173137 - 2²² = 18908978833 is a prime.

It is a super-2 number, since 2×18913173137² (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 (18913173157) 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, 28073 + ... + 196505.

It is an arithmetic number, because the mean of its divisors is an integer number (4728363465).

It is a Poulet number, since it divides 2^18913173136-1.

Almost surely, 2^18913173137 is an apocalyptic number.

18913173137 is the 112289-th pentagonal number.

It is an amenable number.

18913173137 is a deficient number, since it is larger than the sum of its proper divisors (280723).

18913173137 is a wasteful number, since it uses less digits than its factorization.

18913173137 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 280722.

The product of its digits is 95256, while the sum is 44.

The spelling of 18913173137 in words is "eighteen billion, nine hundred thirteen million, one hundred seventy-three thousand, one hundred thirty-seven".