18211000891 has 2 divisors, whose sum is σ = 18211000892. Its totient is φ = 18211000890.

The previous prime is 18211000883. The next prime is 18211000931. The reversal of 18211000891 is 19800011281.

It is a weak prime.

It is an emirp because it is prime and its reverse (19800011281) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18211000891 - 2³ = 18211000883 is a prime.

It is not a weakly prime, because it can be changed into another prime (18211000811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9105500445 + 9105500446.

It is an arithmetic number, because the mean of its divisors is an integer number (9105500446).

Almost surely, 2^18211000891 is an apocalyptic number.

18211000891 is a deficient number, since it is larger than the sum of its proper divisors (1).

18211000891 is an equidigital number, since it uses as much as digits as its factorization.

18211000891 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1152, while the sum is 31.

The spelling of 18211000891 in words is "eighteen billion, two hundred eleven million, eight hundred ninety-one", and thus it is an aban number.