21155103 has 6 divisors (see below), whose sum is σ = 30557384. Its totient is φ = 14103396.

The previous prime is 21155087. The next prime is 21155107. The reversal of 21155103 is 30155112.

It is not a de Polignac number, because 21155103 - 2⁴ = 21155087 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 (21155107) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1175275 + ... + 1175292.

Almost surely, 2^21155103 is an apocalyptic number.

21155103 is a deficient number, since it is larger than the sum of its proper divisors (9402281).

21155103 is a wasteful number, since it uses less digits than its factorization.

21155103 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2350573 (or 2350570 counting only the distinct ones).

The product of its (nonzero) digits is 150, while the sum is 18.

The square root of 21155103 is about 4599.4676865916. The cubic root of 21155103 is about 276.5699862189.

Subtracting 21155103 from its reverse (30155112), we obtain a palindrome (9000009).

The spelling of 21155103 in words is "twenty-one million, one hundred fifty-five thousand, one hundred three".