21156103 has 4 divisors (see below), whose sum is σ = 21199000. Its totient is φ = 21113208.

The previous prime is 21156077. The next prime is 21156127. The reversal of 21156103 is 30165112.

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 21156103 - 2⁵ = 21156071 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 (21156403) 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, 20700 + ... + 21697.

It is an arithmetic number, because the mean of its divisors is an integer number (5299750).

Almost surely, 2^21156103 is an apocalyptic number.

21156103 is a deficient number, since it is larger than the sum of its proper divisors (42897).

21156103 is an equidigital number, since it uses as much as digits as its factorization.

21156103 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42896.

The product of its (nonzero) digits is 180, while the sum is 19.

The square root of 21156103 is about 4599.5763935389. The cubic root of 21156103 is about 276.5743439638.

Subtracting 21156103 from its reverse (30165112), we obtain a palindrome (9009009).

The spelling of 21156103 in words is "twenty-one million, one hundred fifty-six thousand, one hundred three".