21254603 has 4 divisors (see below), whose sum is σ = 21289560. Its totient is φ = 21219648.

The previous prime is 21254581. The next prime is 21254617. The reversal of 21254603 is 30645212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21254603 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21254633) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16550 + ... + 17787.

It is an arithmetic number, because the mean of its divisors is an integer number (5322390).

Almost surely, 2^21254603 is an apocalyptic number.

21254603 is a deficient number, since it is larger than the sum of its proper divisors (34957).

21254603 is an equidigital number, since it uses as much as digits as its factorization.

21254603 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34956.

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 21254603 is about 4610.2714670613. The cubic root of 21254603 is about 277.0029106464.

Adding to 21254603 its reverse (30645212), we get a palindrome (51899815).

The spelling of 21254603 in words is "twenty-one million, two hundred fifty-four thousand, six hundred three".