18152994781 has 4 divisors (see below), whose sum is σ = 18153276700. Its totient is φ = 18152712864.

The previous prime is 18152994731. The next prime is 18152994829. The reversal of 18152994781 is 18749925181.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18749925181 = 13 ⋅1442301937.

It can be written as a sum of positive squares in 2 ways, for example, as 9449784100 + 8703210681 = 97210^2 + 93291^2 .

It is a cyclic number.

It is not a de Polignac number, because 18152994781 - 2⁷ = 18152994653 is a prime.

It is a super-2 number, since 2×18152994781² (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 (18152994731) 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, 8335 + ... + 190723.

It is an arithmetic number, because the mean of its divisors is an integer number (4538319175).

Almost surely, 2^18152994781 is an apocalyptic number.

It is an amenable number.

18152994781 is a deficient number, since it is larger than the sum of its proper divisors (281919).

18152994781 is an equidigital number, since it uses as much as digits as its factorization.

18152994781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 281918.

The product of its digits is 1451520, while the sum is 55.

The spelling of 18152994781 in words is "eighteen billion, one hundred fifty-two million, nine hundred ninety-four thousand, seven hundred eighty-one".