21385503 has 6 divisors (see below), whose sum is σ = 30890184. Its totient is φ = 14256996.

The previous prime is 21385471. The next prime is 21385513. The reversal of 21385503 is 30558312.

It is not a de Polignac number, because 21385503 - 2⁵ = 21385471 is a prime.

It is a super-3 number, since 3×21385503³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21385513) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1188075 + ... + 1188092.

It is an arithmetic number, because the mean of its divisors is an integer number (5148364).

Almost surely, 2^21385503 is an apocalyptic number.

21385503 is a deficient number, since it is larger than the sum of its proper divisors (9504681).

21385503 is a wasteful number, since it uses less digits than its factorization.

21385503 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2376173 (or 2376170 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

The square root of 21385503 is about 4624.4462371186. The cubic root of 21385503 is about 277.5704033688.

The spelling of 21385503 in words is "twenty-one million, three hundred eighty-five thousand, five hundred three".