21440243401 has 4 divisors (see below), whose sum is σ = 21460644304. Its totient is φ = 21419842500.

The previous prime is 21440243351. The next prime is 21440243491. The reversal of 21440243401 is 10434204412.

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 a cyclic number.

It is not a de Polignac number, because 21440243401 - 2¹¹ = 21440241353 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21440243491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10198875 + ... + 10200976.

It is an arithmetic number, because the mean of its divisors is an integer number (5365161076).

Almost surely, 2^21440243401 is an apocalyptic number.

It is an amenable number.

21440243401 is a deficient number, since it is larger than the sum of its proper divisors (20400903).

21440243401 is a wasteful number, since it uses less digits than its factorization.

21440243401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20400902.

The product of its (nonzero) digits is 3072, while the sum is 25.

Adding to 21440243401 its reverse (10434204412), we get a palindrome (31874447813).

The spelling of 21440243401 in words is "twenty-one billion, four hundred forty million, two hundred forty-three thousand, four hundred one".