18228776861 has 2 divisors, whose sum is σ = 18228776862. Its totient is φ = 18228776860.

The previous prime is 18228776857. The next prime is 18228776873. The reversal of 18228776861 is 16867782281.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18014739961 + 214036900 = 134219^2 + 14630^2 .

It is a cyclic number.

It is not a de Polignac number, because 18228776861 - 2² = 18228776857 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 18228776797 and 18228776806.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18228776831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9114388430 + 9114388431.

It is an arithmetic number, because the mean of its divisors is an integer number (9114388431).

Almost surely, 2^18228776861 is an apocalyptic number.

It is an amenable number.

18228776861 is a deficient number, since it is larger than the sum of its proper divisors (1).

18228776861 is an equidigital number, since it uses as much as digits as its factorization.

18228776861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3612672, while the sum is 56.

The spelling of 18228776861 in words is "eighteen billion, two hundred twenty-eight million, seven hundred seventy-six thousand, eight hundred sixty-one".