21396314721 has 8 divisors (see below), whose sum is σ = 28560731680. Its totient is φ = 14248053792.

The previous prime is 21396314717. The next prime is 21396314743. The reversal of 21396314721 is 12741369312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21396314721 - 2² = 21396314717 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21396314721.

It is not an unprimeable number, because it can be changed into a prime (21396314701) 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 7 ways as a sum of consecutive naturals, for example, 4035916 + ... + 4041213.

It is an arithmetic number, because the mean of its divisors is an integer number (3570091460).

Almost surely, 2^21396314721 is an apocalyptic number.

It is an amenable number.

21396314721 is a deficient number, since it is larger than the sum of its proper divisors (7164416959).

21396314721 is an equidigital number, since it uses as much as digits as its factorization.

21396314721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8078015.

The product of its digits is 54432, while the sum is 39.

The spelling of 21396314721 in words is "twenty-one billion, three hundred ninety-six million, three hundred fourteen thousand, seven hundred twenty-one".