21003113 has 4 divisors (see below), whose sum is σ = 22108560. Its totient is φ = 19897668.

The previous prime is 21003107. The next prime is 21003121. The reversal of 21003113 is 31130012.

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 21003113 - 2⁴ = 21003097 is a prime.

It is a super-2 number, since 2×21003113² = 882261511381538, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21003094 and 21003103.

It is not an unprimeable number, because it can be changed into a prime (21003173) 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, 552695 + ... + 552732.

It is an arithmetic number, because the mean of its divisors is an integer number (5527140).

Almost surely, 2^21003113 is an apocalyptic number.

It is an amenable number.

21003113 is a deficient number, since it is larger than the sum of its proper divisors (1105447).

21003113 is a wasteful number, since it uses less digits than its factorization.

21003113 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1105446.

The product of its (nonzero) digits is 18, while the sum is 11.

The square root of 21003113 is about 4582.9153385154. The cubic root of 21003113 is about 275.9060495534.

Adding to 21003113 its reverse (31130012), we get a palindrome (52133125).

The spelling of 21003113 in words is "twenty-one million, three thousand, one hundred thirteen".