18277120661 has 4 divisors (see below), whose sum is σ = 19239074400. Its totient is φ = 17315166924.

The previous prime is 18277120643. The next prime is 18277120679. The reversal of 18277120661 is 16602177281.

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, and also an emirpimes, since its reverse is a distinct semiprime: 16602177281 = 54049 ⋅307169.

It is an interprime number because it is at equal distance from previous prime (18277120643) and next prime (18277120679).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18277120661 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18277110661) 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, 480976841 + ... + 480976878.

It is an arithmetic number, because the mean of its divisors is an integer number (4809768600).

Almost surely, 2^18277120661 is an apocalyptic number.

It is an amenable number.

18277120661 is a deficient number, since it is larger than the sum of its proper divisors (961953739).

18277120661 is an equidigital number, since it uses as much as digits as its factorization.

18277120661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 961953738.

The product of its (nonzero) digits is 56448, while the sum is 41.

The spelling of 18277120661 in words is "eighteen billion, two hundred seventy-seven million, one hundred twenty thousand, six hundred sixty-one".