18818156381 has 4 divisors (see below), whose sum is σ = 18857443200. Its totient is φ = 18778869564.

The previous prime is 18818156333. The next prime is 18818156407. The reversal of 18818156381 is 18365181881.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 18818156381 - 2¹⁰ = 18818155357 is a prime.

It is a super-2 number, since 2×18818156381² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18818156311) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19642691 + ... + 19643648.

It is an arithmetic number, because the mean of its divisors is an integer number (4714360800).

Almost surely, 2^18818156381 is an apocalyptic number.

It is an amenable number.

18818156381 is a deficient number, since it is larger than the sum of its proper divisors (39286819).

18818156381 is an equidigital number, since it uses as much as digits as its factorization.

18818156381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39286818.

The product of its digits is 368640, while the sum is 50.

The spelling of 18818156381 in words is "eighteen billion, eight hundred eighteen million, one hundred fifty-six thousand, three hundred eighty-one".