21243340801 has 4 divisors (see below), whose sum is σ = 21286962112. Its totient is φ = 21199719492.

The previous prime is 21243340747. The next prime is 21243340819. The reversal of 21243340801 is 10804334212.

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 21243340801 - 2¹⁹ = 21242816513 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21243340801.

It is not an unprimeable number, because it can be changed into a prime (21243340831) 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, 21809925 + ... + 21810898.

It is an arithmetic number, because the mean of its divisors is an integer number (5321740528).

Almost surely, 2^21243340801 is an apocalyptic number.

It is an amenable number.

21243340801 is a deficient number, since it is larger than the sum of its proper divisors (43621311).

21243340801 is an equidigital number, since it uses as much as digits as its factorization.

21243340801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43621310.

The product of its (nonzero) digits is 4608, while the sum is 28.

The spelling of 21243340801 in words is "twenty-one billion, two hundred forty-three million, three hundred forty thousand, eight hundred one".