21002111 has 8 divisors (see below), whose sum is σ = 22668240. Its totient is φ = 19343232.

The previous prime is 21002101. The next prime is 21002129. The reversal of 21002111 is 11120012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21002111 - 2¹⁰ = 21001087 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 (21002101) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5255 + ... + 8343.

It is an arithmetic number, because the mean of its divisors is an integer number (2833530).

Almost surely, 2^21002111 is an apocalyptic number.

21002111 is a deficient number, since it is larger than the sum of its proper divisors (1666129).

21002111 is a wasteful number, since it uses less digits than its factorization.

21002111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3625.

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

The square root of 21002111 is about 4582.8060181509. The cubic root of 21002111 is about 275.9016619140.

Adding to 21002111 its reverse (11120012), we get a palindrome (32122123).

The spelling of 21002111 in words is "twenty-one million, two thousand, one hundred eleven".