21120111101987 has 2 divisors, whose sum is σ = 21120111101988. Its totient is φ = 21120111101986.

The previous prime is 21120111101983. The next prime is 21120111102179. The reversal of 21120111101987 is 78910111102112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21120111101987 - 2² = 21120111101983 is a prime.

It is not a weakly prime, because it can be changed into another prime (21120111101981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560055550993 + 10560055550994.

It is an arithmetic number, because the mean of its divisors is an integer number (10560055550994).

Almost surely, 2^{21120111101987} is an apocalyptic number.

21120111101987 is a deficient number, since it is larger than the sum of its proper divisors (1).

21120111101987 is an equidigital number, since it uses as much as digits as its factorization.

21120111101987 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2016, while the sum is 35.

The spelling of 21120111101987 in words is "twenty-one trillion, one hundred twenty billion, one hundred eleven million, one hundred one thousand, nine hundred eighty-seven".