19945447723 has 4 divisors (see below), whose sum is σ = 19999795360. Its totient is φ = 19891100088.

The previous prime is 19945447699. The next prime is 19945447747. The reversal of 19945447723 is 32774454991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 32774454991 = 41 ⋅799376951.

It is an interprime number because it is at equal distance from previous prime (19945447699) and next prime (19945447747).

It is a cyclic number.

It is not a de Polignac number, because 19945447723 - 2³³ = 11355513131 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19945447793) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27173268 + ... + 27174001.

It is an arithmetic number, because the mean of its divisors is an integer number (4999948840).

Almost surely, 2^19945447723 is an apocalyptic number.

19945447723 is a deficient number, since it is larger than the sum of its proper divisors (54347637).

19945447723 is an equidigital number, since it uses as much as digits as its factorization.

19945447723 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54347636.

The product of its digits is 7620480, while the sum is 55.

The spelling of 19945447723 in words is "nineteen billion, nine hundred forty-five million, four hundred forty-seven thousand, seven hundred twenty-three".