20191744439 has 2 divisors, whose sum is σ = 20191744440. Its totient is φ = 20191744438.

The previous prime is 20191744369. The next prime is 20191744471. The reversal of 20191744439 is 93444719102.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20191744439 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20191744439.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20191741439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10095872219 + 10095872220.

It is an arithmetic number, because the mean of its divisors is an integer number (10095872220).

Almost surely, 2^20191744439 is an apocalyptic number.

20191744439 is a deficient number, since it is larger than the sum of its proper divisors (1).

20191744439 is an equidigital number, since it uses as much as digits as its factorization.

20191744439 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 217728, while the sum is 44.

The spelling of 20191744439 in words is "twenty billion, one hundred ninety-one million, seven hundred forty-four thousand, four hundred thirty-nine".