19591675421 has 2 divisors, whose sum is σ = 19591675422. Its totient is φ = 19591675420.

The previous prime is 19591675403. The next prime is 19591675469. The reversal of 19591675421 is 12457619591.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14264719225 + 5326956196 = 119435^2 + 72986^2 .

It is a cyclic number.

It is not a de Polignac number, because 19591675421 - 2¹⁴ = 19591659037 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 19591675421.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19591675021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9795837710 + 9795837711.

It is an arithmetic number, because the mean of its divisors is an integer number (9795837711).

Almost surely, 2^19591675421 is an apocalyptic number.

It is an amenable number.

19591675421 is a deficient number, since it is larger than the sum of its proper divisors (1).

19591675421 is an equidigital number, since it uses as much as digits as its factorization.

19591675421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 680400, while the sum is 50.

The spelling of 19591675421 in words is "nineteen billion, five hundred ninety-one million, six hundred seventy-five thousand, four hundred twenty-one".