19728321953 has 4 divisors (see below), whose sum is σ = 19803334848. Its totient is φ = 19653309060.

The previous prime is 19728321947. The next prime is 19728321961. The reversal of 19728321953 is 35912382791.

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 19728321953 - 2¹⁸ = 19728059809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19728321923) 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, 37506053 + ... + 37506578.

It is an arithmetic number, because the mean of its divisors is an integer number (4950833712).

Almost surely, 2^19728321953 is an apocalyptic number.

It is an amenable number.

19728321953 is a deficient number, since it is larger than the sum of its proper divisors (75012895).

19728321953 is an equidigital number, since it uses as much as digits as its factorization.

19728321953 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75012894.

The product of its digits is 816480, while the sum is 50.

The spelling of 19728321953 in words is "nineteen billion, seven hundred twenty-eight million, three hundred twenty-one thousand, nine hundred fifty-three".