21011002111 has 4 divisors (see below), whose sum is σ = 22921093224. Its totient is φ = 19100911000.

The previous prime is 21011002087. The next prime is 21011002141. The reversal of 21011002111 is 11120011012.

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

It is a cyclic number.

It is not a de Polignac number, because 21011002111 - 2¹⁹ = 21010477823 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21011002141) 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, 955045540 + ... + 955045561.

It is an arithmetic number, because the mean of its divisors is an integer number (5730273306).

Almost surely, 2^21011002111 is an apocalyptic number.

21011002111 is a deficient number, since it is larger than the sum of its proper divisors (1910091113).

21011002111 is a wasteful number, since it uses less digits than its factorization.

21011002111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1910091112.

The product of its (nonzero) digits is 4, while the sum is 10.

Adding to 21011002111 its reverse (11120011012), we get a palindrome (32131013123).

The spelling of 21011002111 in words is "twenty-one billion, eleven million, two thousand, one hundred eleven".