21111010111001 has 4 divisors (see below), whose sum is σ = 21111105574452. Its totient is φ = 21110914647552.

The previous prime is 21111010110997. The next prime is 21111010111003. The reversal of 21111010111001 is 10011101011112.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9887572091401 + 11223438019600 = 3144451^2 + 3350140^2 .

It is a cyclic number.

It is not a de Polignac number, because 21111010111001 - 2² = 21111010110997 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21111010111003) 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 in 3 ways as a sum of consecutive naturals, for example, 47399240 + ... + 47842553.

It is an arithmetic number, because the mean of its divisors is an integer number (5277776393613).

Almost surely, 2^{21111010111001} is an apocalyptic number.

It is an amenable number.

21111010111001 is a deficient number, since it is larger than the sum of its proper divisors (95463451).

21111010111001 is an equidigital number, since it uses as much as digits as its factorization.

21111010111001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95463450.

The product of its (nonzero) digits is 2, while the sum is 11.

Adding to 21111010111001 its reverse (10011101011112), we get a palindrome (31122111122113).

The spelling of 21111010111001 in words is "twenty-one trillion, one hundred eleven billion, ten million, one hundred eleven thousand, one".