21011110009987 has 2 divisors, whose sum is σ = 21011110009988. Its totient is φ = 21011110009986.

The previous prime is 21011110009951. The next prime is 21011110009991. The reversal of 21011110009987 is 78990001111012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21011110009987 - 2⁷ = 21011110009859 is a prime.

It is a super-2 number, since 2×21011110009987² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21011110009187) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505555004993 + 10505555004994.

It is an arithmetic number, because the mean of its divisors is an integer number (10505555004994).

Almost surely, 2^{21011110009987} is an apocalyptic number.

21011110009987 is a deficient number, since it is larger than the sum of its proper divisors (1).

21011110009987 is an equidigital number, since it uses as much as digits as its factorization.

21011110009987 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9072, while the sum is 40.

The spelling of 21011110009987 in words is "twenty-one trillion, eleven billion, one hundred ten million, nine thousand, nine hundred eighty-seven".