21368503 has 16 divisors (see below), whose sum is σ = 24103296. Its totient is φ = 18812160.

The previous prime is 21368497. The next prime is 21368513. The reversal of 21368503 is 30586312.

It is a cyclic number.

It is not a de Polignac number, because 21368503 - 2⁵ = 21368471 is a prime.

It is a super-2 number, since 2×21368503² = 913225840922018, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21368513) 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 15 ways as a sum of consecutive naturals, for example, 24625 + ... + 25477.

It is an arithmetic number, because the mean of its divisors is an integer number (1506456).

Almost surely, 2^21368503 is an apocalyptic number.

21368503 is a deficient number, since it is larger than the sum of its proper divisors (2734793).

21368503 is a wasteful number, since it uses less digits than its factorization.

21368503 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 954.

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 21368503 is about 4622.6078137778. The cubic root of 21368503 is about 277.4968340953.

The spelling of 21368503 in words is "twenty-one million, three hundred sixty-eight thousand, five hundred three".