21111021010987 has 2 divisors, whose sum is σ = 21111021010988. Its totient is φ = 21111021010986.

The previous prime is 21111021010979. The next prime is 21111021011039. The reversal of 21111021010987 is 78901012011112.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21111021010987 - 2³ = 21111021010979 is a prime.

It is not a weakly prime, because it can be changed into another prime (21111021010687) 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, 10555510505493 + 10555510505494.

It is an arithmetic number, because the mean of its divisors is an integer number (10555510505494).

Almost surely, 2^{21111021010987} is an apocalyptic number.

21111021010987 is a deficient number, since it is larger than the sum of its proper divisors (1).

21111021010987 is an equidigital number, since it uses as much as digits as its factorization.

21111021010987 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 34.

The spelling of 21111021010987 in words is "twenty-one trillion, one hundred eleven billion, twenty-one million, ten thousand, nine hundred eighty-seven".