21052401 has 4 divisors (see below), whose sum is σ = 28069872. Its totient is φ = 14034932.

The previous prime is 21052391. The next prime is 21052411. The reversal of 21052401 is 10425012.

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 an interprime number because it is at equal distance from previous prime (21052391) and next prime (21052411).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21052401 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21052411) 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 in 3 ways as a sum of consecutive naturals, for example, 3508731 + ... + 3508736.

It is an arithmetic number, because the mean of its divisors is an integer number (7017468).

Almost surely, 2^21052401 is an apocalyptic number.

It is an amenable number.

21052401 is a deficient number, since it is larger than the sum of its proper divisors (7017471).

21052401 is an equidigital number, since it uses as much as digits as its factorization.

21052401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7017470.

The product of its (nonzero) digits is 80, while the sum is 15.

The square root of 21052401 is about 4588.2895505842. The cubic root of 21052401 is about 276.1217038350.

Adding to 21052401 its reverse (10425012), we get a palindrome (31477413).

The spelling of 21052401 in words is "twenty-one million, fifty-two thousand, four hundred one".