1918826985821 has 2 divisors, whose sum is σ = 1918826985822. Its totient is φ = 1918826985820.

The previous prime is 1918826985799. The next prime is 1918826985851. The reversal of 1918826985821 is 1285896288191.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1877694684100 + 41132301721 = 1370290^2 + 202811^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1918826985821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1918826985851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 959413492910 + 959413492911.

It is an arithmetic number, because the mean of its divisors is an integer number (959413492911).

Almost surely, 2^{1918826985821} is an apocalyptic number.

It is an amenable number.

1918826985821 is a deficient number, since it is larger than the sum of its proper divisors (1).

1918826985821 is an equidigital number, since it uses as much as digits as its factorization.

1918826985821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 39813120, while the sum is 68.

The spelling of 1918826985821 in words is "one trillion, nine hundred eighteen billion, eight hundred twenty-six million, nine hundred eighty-five thousand, eight hundred twenty-one".