21001000001111 has 4 divisors (see below), whose sum is σ = 22616461539672. Its totient is φ = 19385538462552.

The previous prime is 21001000001101. The next prime is 21001000001141. The reversal of 21001000001111 is 11110000010012.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21001000001111 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001000001101) 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 3 ways as a sum of consecutive naturals, for example, 807730769261 + ... + 807730769286.

It is an arithmetic number, because the mean of its divisors is an integer number (5654115384918).

Almost surely, 2^{21001000001111} is an apocalyptic number.

21001000001111 is a deficient number, since it is larger than the sum of its proper divisors (1615461538561).

21001000001111 is a wasteful number, since it uses less digits than its factorization.

21001000001111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1615461538560.

The product of its (nonzero) digits is 2, while the sum is 8.

Adding to 21001000001111 its reverse (11110000010012), we get a palindrome (32111000011123).

The spelling of 21001000001111 in words is "twenty-one trillion, one billion, one thousand, one hundred eleven".