21110000002001 has 4 divisors (see below), whose sum is σ = 21303669726900. Its totient is φ = 20916330277104.

The previous prime is 21110000001971. The next prime is 21110000002009. The reversal of 21110000002001 is 10020000001112.

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 11745322851025 + 9364677150976 = 3427145^2 + 3060176^2 .

It is a cyclic number.

It is not a de Polignac number, because 21110000002001 - 2²² = 21109995807697 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 21110000002001.

It is not an unprimeable number, because it can be changed into a prime (21110000002009) 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, 96834862286 + ... + 96834862503.

It is an arithmetic number, because the mean of its divisors is an integer number (5325917431725).

Almost surely, 2^{21110000002001} is an apocalyptic number.

It is an amenable number.

21110000002001 is a deficient number, since it is larger than the sum of its proper divisors (193669724899).

21110000002001 is a wasteful number, since it uses less digits than its factorization.

21110000002001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 193669724898.

The product of its (nonzero) digits is 4, while the sum is 8.

Adding to 21110000002001 its reverse (10020000001112), we get a palindrome (31130000003113).

The spelling of 21110000002001 in words is "twenty-one trillion, one hundred ten billion, two thousand, one".