21144401 has 4 divisors (see below), whose sum is σ = 21153600. Its totient is φ = 21135204.

The previous prime is 21144373. The next prime is 21144419. The reversal of 21144401 is 10444112.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21144401 - 2¹⁰ = 21143377 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21144401.

It is not an unprimeable number, because it can be changed into a prime (21144301) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2180 + ... + 6858.

It is an arithmetic number, because the mean of its divisors is an integer number (5288400).

Almost surely, 2^21144401 is an apocalyptic number.

It is an amenable number.

21144401 is a deficient number, since it is larger than the sum of its proper divisors (9199).

21144401 is an equidigital number, since it uses as much as digits as its factorization.

21144401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9198.

The product of its (nonzero) digits is 128, while the sum is 17.

The square root of 21144401 is about 4598.3041439209. The cubic root of 21144401 is about 276.5233410313.

Adding to 21144401 its reverse (10444112), we get a palindrome (31588513).

The spelling of 21144401 in words is "twenty-one million, one hundred forty-four thousand, four hundred one".