21000111011001 has 24 divisors (see below), whose sum is σ = 31999255928640. Its totient is φ = 13234457397600.

The previous prime is 21000111010981. The next prime is 21000111011041. The reversal of 21000111011001 is 10011011100012.

It is not a de Polignac number, because 21000111011001 - 2⁶ = 21000111010937 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 (21000111011041) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 133118205 + ... + 133275866.

It is an arithmetic number, because the mean of its divisors is an integer number (1333302330360).

Almost surely, 2^{21000111011001} is an apocalyptic number.

It is an amenable number.

21000111011001 is a deficient number, since it is larger than the sum of its proper divisors (10999144917639).

21000111011001 is a wasteful number, since it uses less digits than its factorization.

21000111011001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 266394557 (or 266394554 counting only the distinct ones).

The product of its (nonzero) digits is 2, while the sum is 9.

Adding to 21000111011001 its reverse (10011011100012), we get a palindrome (31011122111013).

The spelling of 21000111011001 in words is "twenty-one trillion, one hundred eleven million, eleven thousand, one".