18691277881 has 4 divisors (see below), whose sum is σ = 18695348452. Its totient is φ = 18687207312.

The previous prime is 18691277849. The next prime is 18691277887. The reversal of 18691277881 is 18877219681.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1357185600 + 17334092281 = 36840^2 + 131659^2 .

It is a cyclic number.

It is not a de Polignac number, because 18691277881 - 2⁵ = 18691277849 is a prime.

It is a super-2 number, since 2×18691277881² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18691277887) 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, 2028390 + ... + 2037583.

It is an arithmetic number, because the mean of its divisors is an integer number (4673837113).

Almost surely, 2^18691277881 is an apocalyptic number.

It is an amenable number.

18691277881 is a deficient number, since it is larger than the sum of its proper divisors (4070571).

18691277881 is an equidigital number, since it uses as much as digits as its factorization.

18691277881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4070570.

The product of its digits is 2709504, while the sum is 58.

The spelling of 18691277881 in words is "eighteen billion, six hundred ninety-one million, two hundred seventy-seven thousand, eight hundred eighty-one".