21665201339 has 4 divisors (see below), whose sum is σ = 21669730080. Its totient is φ = 21660672600.

The previous prime is 21665201329. The next prime is 21665201423. The reversal of 21665201339 is 93310256612.

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

It is a cyclic number.

It is not a de Polignac number, because 21665201339 - 2⁸ = 21665201083 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21665201329) 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, 2257187 + ... + 2266764.

It is an arithmetic number, because the mean of its divisors is an integer number (5417432520).

Almost surely, 2^21665201339 is an apocalyptic number.

21665201339 is a deficient number, since it is larger than the sum of its proper divisors (4528741).

21665201339 is an equidigital number, since it uses as much as digits as its factorization.

21665201339 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4528740.

The product of its (nonzero) digits is 58320, while the sum is 38.

The spelling of 21665201339 in words is "twenty-one billion, six hundred sixty-five million, two hundred one thousand, three hundred thirty-nine".