21004440403 has 2 divisors, whose sum is σ = 21004440404. Its totient is φ = 21004440402.

The previous prime is 21004440377. The next prime is 21004440467. The reversal of 21004440403 is 30404440012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21004440403 - 2²¹ = 21002343251 is a prime.

It is not a weakly prime, because it can be changed into another prime (21004440503) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10502220201 + 10502220202.

It is an arithmetic number, because the mean of its divisors is an integer number (10502220202).

Almost surely, 2^21004440403 is an apocalyptic number.

21004440403 is a deficient number, since it is larger than the sum of its proper divisors (1).

21004440403 is an equidigital number, since it uses as much as digits as its factorization.

21004440403 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1536, while the sum is 22.

Adding to 21004440403 its reverse (30404440012), we get a palindrome (51408880415).

The spelling of 21004440403 in words is "twenty-one billion, four million, four hundred forty thousand, four hundred three".