18381591373 has 2 divisors, whose sum is σ = 18381591374. Its totient is φ = 18381591372.

The previous prime is 18381591353. The next prime is 18381591409. The reversal of 18381591373 is 37319518381.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17645934244 + 735657129 = 132838^2 + 27123^2 .

It is an emirp because it is prime and its reverse (37319518381) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18381591373 - 2⁵ = 18381591341 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18381591323) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9190795686 + 9190795687.

It is an arithmetic number, because the mean of its divisors is an integer number (9190795687).

Almost surely, 2^18381591373 is an apocalyptic number.

It is an amenable number.

18381591373 is a deficient number, since it is larger than the sum of its proper divisors (1).

18381591373 is an equidigital number, since it uses as much as digits as its factorization.

18381591373 is an evil number, because the sum of its binary digits is even.

The product of its digits is 544320, while the sum is 49.

The spelling of 18381591373 in words is "eighteen billion, three hundred eighty-one million, five hundred ninety-one thousand, three hundred seventy-three".