21603047 has 2 divisors, whose sum is σ = 21603048. Its totient is φ = 21603046.

The previous prime is 21603017. The next prime is 21603053. The reversal of 21603047 is 74030612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21603047 - 2²⁴ = 4825831 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21603007) 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, 10801523 + 10801524.

It is an arithmetic number, because the mean of its divisors is an integer number (10801524).

Almost surely, 2^21603047 is an apocalyptic number.

21603047 is a deficient number, since it is larger than the sum of its proper divisors (1).

21603047 is an equidigital number, since it uses as much as digits as its factorization.

21603047 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1008, while the sum is 23.

The square root of 21603047 is about 4647.9078088964. The cubic root of 21603047 is about 278.5084246984.

Adding to 21603047 its reverse (74030612), we get a palindrome (95633659).

The spelling of 21603047 in words is "twenty-one million, six hundred three thousand, forty-seven".