19387897 has 2 divisors, whose sum is σ = 19387898. Its totient is φ = 19387896.

The previous prime is 19387891. The next prime is 19387909. The reversal of 19387897 is 79878391.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12931216 + 6456681 = 3596^2 + 2541^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19387897 is a prime.

It is not a weakly prime, because it can be changed into another prime (19387891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9693948 + 9693949.

It is an arithmetic number, because the mean of its divisors is an integer number (9693949).

Almost surely, 2^19387897 is an apocalyptic number.

It is an amenable number.

19387897 is a deficient number, since it is larger than the sum of its proper divisors (1).

19387897 is an equidigital number, since it uses as much as digits as its factorization.

19387897 is an evil number, because the sum of its binary digits is even.

The product of its digits is 762048, while the sum is 52.

The square root of 19387897 is about 4403.1689724561. The cubic root of 19387897 is about 268.6438490461.

The spelling of 19387897 in words is "nineteen million, three hundred eighty-seven thousand, eight hundred ninety-seven".