19375728721 has 2 divisors, whose sum is σ = 19375728722. Its totient is φ = 19375728720.

The previous prime is 19375728707. The next prime is 19375728769. The reversal of 19375728721 is 12782757391.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19071610000 + 304118721 = 138100^2 + 17439^2 .

It is a cyclic number.

It is not a de Polignac number, because 19375728721 - 2⁵ = 19375728689 is a prime.

It is not a weakly prime, because it can be changed into another prime (19375728821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9687864360 + 9687864361.

It is an arithmetic number, because the mean of its divisors is an integer number (9687864361).

Almost surely, 2^19375728721 is an apocalyptic number.

It is an amenable number.

19375728721 is a deficient number, since it is larger than the sum of its proper divisors (1).

19375728721 is an equidigital number, since it uses as much as digits as its factorization.

19375728721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1481760, while the sum is 52.

The spelling of 19375728721 in words is "nineteen billion, three hundred seventy-five million, seven hundred twenty-eight thousand, seven hundred twenty-one".