21243004207 has 6 divisors (see below), whose sum is σ = 22419902328. Its totient is φ = 20124951012.

The previous prime is 21243004193. The next prime is 21243004219. The reversal of 21243004207 is 70240034212.

It is a happy number.

It is not a de Polignac number, because 21243004207 - 2¹⁵ = 21242971439 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21243004507) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 29422083 + ... + 29422804.

It is an arithmetic number, because the mean of its divisors is an integer number (3736650388).

Almost surely, 2^21243004207 is an apocalyptic number.

21243004207 is a deficient number, since it is larger than the sum of its proper divisors (1176898121).

21243004207 is an equidigital number, since it uses as much as digits as its factorization.

21243004207 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58844925 (or 58844906 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 25.

Adding to 21243004207 its reverse (70240034212), we get a palindrome (91483038419).

The spelling of 21243004207 in words is "twenty-one billion, two hundred forty-three million, four thousand, two hundred seven".