21011111010001 has 4 divisors (see below), whose sum is σ = 24012698297152. Its totient is φ = 18009523722852.

The previous prime is 21011111009969. The next prime is 21011111010037. The reversal of 21011111010001 is 10001011111012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21011111010001 - 2⁵ = 21011111009969 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21011111010001.

It is not an unprimeable number, because it can be changed into a prime (21011111010601) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1500793643565 + ... + 1500793643578.

It is an arithmetic number, because the mean of its divisors is an integer number (6003174574288).

Almost surely, 2^{21011111010001} is an apocalyptic number.

It is an amenable number.

21011111010001 is a deficient number, since it is larger than the sum of its proper divisors (3001587287151).

21011111010001 is an equidigital number, since it uses as much as digits as its factorization.

21011111010001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3001587287150.

The product of its (nonzero) digits is 2, while the sum is 10.

Adding to 21011111010001 its reverse (10001011111012), we get a palindrome (31012122121013).

The spelling of 21011111010001 in words is "twenty-one trillion, eleven billion, one hundred eleven million, ten thousand, one".