21000021110001 has 24 divisors (see below), whose sum is σ = 31661145612096. Its totient is φ = 13387535552160.

The previous prime is 21000021109901. The next prime is 21000021110023. The reversal of 21000021110001 is 10001112000012.

It is a happy number.

It is not a de Polignac number, because 21000021110001 - 2⁹ = 21000021109489 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is not an unprimeable number, because it can be changed into a prime (21000021110051) 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 in 23 ways as a sum of consecutive naturals, for example, 13591975 + ... + 15057948.

It is an arithmetic number, because the mean of its divisors is an integer number (1319214400504).

Almost surely, 2^{21000021110001} is an apocalyptic number.

It is an amenable number.

21000021110001 is a deficient number, since it is larger than the sum of its proper divisors (10661124502095).

21000021110001 is a wasteful number, since it uses less digits than its factorization.

21000021110001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28653493 (or 28653490 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 21000021110001 its reverse (10001112000012), we get a palindrome (31001133110013).

The spelling of 21000021110001 in words is "twenty-one trillion, twenty-one million, one hundred ten thousand, one".