21085103 has 4 divisors (see below), whose sum is σ = 22707048. Its totient is φ = 19463160.

The previous prime is 21085091. The next prime is 21085109. The reversal of 21085103 is 30158012.

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 21085103 - 2⁴ = 21085087 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21085109) 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, 810953 + ... + 810978.

It is an arithmetic number, because the mean of its divisors is an integer number (5676762).

Almost surely, 2^21085103 is an apocalyptic number.

21085103 is a deficient number, since it is larger than the sum of its proper divisors (1621945).

21085103 is a wasteful number, since it uses less digits than its factorization.

21085103 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1621944.

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 21085103 is about 4591.8518051000. The cubic root of 21085103 is about 276.2646021915.

The spelling of 21085103 in words is "twenty-one million, eighty-five thousand, one hundred three".