21404401001 has 4 divisors (see below), whose sum is σ = 21926459604. Its totient is φ = 20882342400.

The previous prime is 21404400977. The next prime is 21404401043. The reversal of 21404401001 is 10010440412.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11142913600 + 10261487401 = 105560^2 + 101299^2 .

It is a cyclic number.

It is not a de Polignac number, because 21404401001 - 2⁶ = 21404400937 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21404401201) 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, 261029240 + ... + 261029321.

It is an arithmetic number, because the mean of its divisors is an integer number (5481614901).

Almost surely, 2^21404401001 is an apocalyptic number.

It is an amenable number.

21404401001 is a deficient number, since it is larger than the sum of its proper divisors (522058603).

21404401001 is an equidigital number, since it uses as much as digits as its factorization.

21404401001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 522058602.

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

Adding to 21404401001 its reverse (10010440412), we get a palindrome (31414841413).

The spelling of 21404401001 in words is "twenty-one billion, four hundred four million, four hundred one thousand, one".