21005301 has 4 divisors (see below), whose sum is σ = 28007072. Its totient is φ = 14003532.

The previous prime is 21005297. The next prime is 21005311. The reversal of 21005301 is 10350012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21005301 - 2² = 21005297 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21005311) 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, 3500881 + ... + 3500886.

It is an arithmetic number, because the mean of its divisors is an integer number (7001768).

Almost surely, 2^21005301 is an apocalyptic number.

It is an amenable number.

21005301 is a deficient number, since it is larger than the sum of its proper divisors (7001771).

21005301 is an equidigital number, since it uses as much as digits as its factorization.

21005301 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7001770.

The product of its (nonzero) digits is 30, while the sum is 12.

The square root of 21005301 is about 4583.1540449782. The cubic root of 21005301 is about 275.9156300613.

Adding to 21005301 its reverse (10350012), we get a palindrome (31355313).

The spelling of 21005301 in words is "twenty-one million, five thousand, three hundred one".