18916817861 has 4 divisors (see below), whose sum is σ = 19527037824. Its totient is φ = 18306597900.

The previous prime is 18916817837. The next prime is 18916817863. The reversal of 18916817861 is 16871861981.

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 18916817861 - 2¹⁰ = 18916816837 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18916817797 and 18916817806.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18916817863) 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, 305109935 + ... + 305109996.

It is an arithmetic number, because the mean of its divisors is an integer number (4881759456).

Almost surely, 2^18916817861 is an apocalyptic number.

It is an amenable number.

18916817861 is a deficient number, since it is larger than the sum of its proper divisors (610219963).

18916817861 is an equidigital number, since it uses as much as digits as its factorization.

18916817861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 610219962.

The product of its digits is 1161216, while the sum is 56.

The spelling of 18916817861 in words is "eighteen billion, nine hundred sixteen million, eight hundred seventeen thousand, eight hundred sixty-one".