19923729409 has 2 divisors, whose sum is σ = 19923729410. Its totient is φ = 19923729408.

The previous prime is 19923729389. The next prime is 19923729421. The reversal of 19923729409 is 90492732991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19901309184 + 22420225 = 141072^2 + 4735^2 .

It is an emirp because it is prime and its reverse (90492732991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19923729409 - 2²³ = 19915340801 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 19923729409.

It is not a weakly prime, because it can be changed into another prime (19923724409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9961864704 + 9961864705.

It is an arithmetic number, because the mean of its divisors is an integer number (9961864705).

Almost surely, 2^19923729409 is an apocalyptic number.

It is an amenable number.

19923729409 is a deficient number, since it is larger than the sum of its proper divisors (1).

19923729409 is an equidigital number, since it uses as much as digits as its factorization.

19923729409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2204496, while the sum is 55.

The spelling of 19923729409 in words is "nineteen billion, nine hundred twenty-three million, seven hundred twenty-nine thousand, four hundred nine".