19997357 has 2 divisors, whose sum is σ = 19997358. Its totient is φ = 19997356.

The previous prime is 19997339. The next prime is 19997399. The reversal of 19997357 is 75379991.

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., 15413476 + 4583881 = 3926^2 + 2141^2 .

It is a cyclic number.

It is not a de Polignac number, because 19997357 - 2¹² = 19993261 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19997317) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9998678 + 9998679.

It is an arithmetic number, because the mean of its divisors is an integer number (9998679).

Almost surely, 2^19997357 is an apocalyptic number.

It is an amenable number.

19997357 is a deficient number, since it is larger than the sum of its proper divisors (1).

19997357 is an equidigital number, since it uses as much as digits as its factorization.

19997357 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 535815, while the sum is 50.

The square root of 19997357 is about 4471.8404488532. The cubic root of 19997357 is about 271.4298041231.

The spelling of 19997357 in words is "nineteen million, nine hundred ninety-seven thousand, three hundred fifty-seven".