18208381487 has 4 divisors (see below), whose sum is σ = 18226645656. Its totient is φ = 18190117320.

The previous prime is 18208381441. The next prime is 18208381493. The reversal of 18208381487 is 78418380281.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78418380281 = 1283 ⋅61121107.

It is a cyclic number.

It is not a de Polignac number, because 18208381487 - 2¹⁴ = 18208365103 is a prime.

It is a super-2 number, since 2×18208381487² (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 (18208381427) 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, 9130589 + ... + 9132582.

It is an arithmetic number, because the mean of its divisors is an integer number (4556661414).

Almost surely, 2^18208381487 is an apocalyptic number.

18208381487 is a deficient number, since it is larger than the sum of its proper divisors (18264169).

18208381487 is an equidigital number, since it uses as much as digits as its factorization.

18208381487 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18264168.

The product of its (nonzero) digits is 688128, while the sum is 50.

The spelling of 18208381487 in words is "eighteen billion, two hundred eight million, three hundred eighty-one thousand, four hundred eighty-seven".