21021113 has 4 divisors (see below), whose sum is σ = 21217680. Its totient is φ = 20824548.

The previous prime is 21021107. The next prime is 21021127. The reversal of 21021113 is 31112012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21021113 - 2¹⁰ = 21020089 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21021094 and 21021103.

It is not an unprimeable number, because it can be changed into a prime (21021713) 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, 98123 + ... + 98336.

It is an arithmetic number, because the mean of its divisors is an integer number (5304420).

Almost surely, 2^21021113 is an apocalyptic number.

It is an amenable number.

21021113 is a deficient number, since it is larger than the sum of its proper divisors (196567).

21021113 is a wasteful number, since it uses less digits than its factorization.

21021113 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 196566.

The product of its (nonzero) digits is 12, while the sum is 11.

The square root of 21021113 is about 4584.8787334018. The cubic root of 21021113 is about 275.9848456638.

Adding to 21021113 its reverse (31112012), we get a palindrome (52133125).

The spelling of 21021113 in words is "twenty-one million, twenty-one thousand, one hundred thirteen".