18381887961 has 8 divisors (see below), whose sum is σ = 24578616480. Its totient is φ = 12219875712.

The previous prime is 18381887947. The next prime is 18381887987. The reversal of 18381887961 is 16978818381.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 18381887961 - 2³⁴ = 1202018777 is a prime.

It is a super-3 number, since 3×18381887961³ (a number of 32 digits) contains 333 as substring.

It is a Smith number, since the sum of its digits (60) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 18381887895 and 18381887904.

It is not an unprimeable number, because it can be changed into a prime (18381887921) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8677831 + ... + 8679948.

It is an arithmetic number, because the mean of its divisors is an integer number (3072327060).

Almost surely, 2^18381887961 is an apocalyptic number.

It is an amenable number.

18381887961 is a deficient number, since it is larger than the sum of its proper divisors (6196728519).

18381887961 is a wasteful number, since it uses less digits than its factorization.

18381887961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17358135.

The product of its digits is 4644864, while the sum is 60.

The spelling of 18381887961 in words is "eighteen billion, three hundred eighty-one million, eight hundred eighty-seven thousand, nine hundred sixty-one".