21457603 has 2 divisors, whose sum is σ = 21457604. Its totient is φ = 21457602.

The previous prime is 21457523. The next prime is 21457627. The reversal of 21457603 is 30675412.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21457603 is a prime.

It is not a weakly prime, because it can be changed into another prime (21457703) 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 as a sum of consecutive naturals, namely, 10728801 + 10728802.

It is an arithmetic number, because the mean of its divisors is an integer number (10728802).

Almost surely, 2^21457603 is an apocalyptic number.

21457603 is a deficient number, since it is larger than the sum of its proper divisors (1).

21457603 is an equidigital number, since it uses as much as digits as its factorization.

21457603 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5040, while the sum is 28.

The square root of 21457603 is about 4632.2352056000. The cubic root of 21457603 is about 277.8819910428.

The spelling of 21457603 in words is "twenty-one million, four hundred fifty-seven thousand, six hundred three".