19738049521 has 2 divisors, whose sum is σ = 19738049522. Its totient is φ = 19738049520.

The previous prime is 19738049497. The next prime is 19738049543. The reversal of 19738049521 is 12594083791.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18329098225 + 1408951296 = 135385^2 + 37536^2 .

It is a cyclic number.

It is not a de Polignac number, because 19738049521 - 2¹⁷ = 19737918449 is a prime.

It is not a weakly prime, because it can be changed into another prime (19738049321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9869024760 + 9869024761.

It is an arithmetic number, because the mean of its divisors is an integer number (9869024761).

Almost surely, 2^19738049521 is an apocalyptic number.

It is an amenable number.

19738049521 is a deficient number, since it is larger than the sum of its proper divisors (1).

19738049521 is an equidigital number, since it uses as much as digits as its factorization.

19738049521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 544320, while the sum is 49.

The spelling of 19738049521 in words is "nineteen billion, seven hundred thirty-eight million, forty-nine thousand, five hundred twenty-one".