19997398 has 4 divisors (see below), whose sum is σ = 29996100. Its totient is φ = 9998698.

The previous prime is 19997357. The next prime is 19997399. The reversal of 19997398 is 89379991.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19997399) 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, 4999348 + ... + 4999351.

It is an arithmetic number, because the mean of its divisors is an integer number (7499025).

Almost surely, 2^19997398 is an apocalyptic number.

19997398 is a deficient number, since it is larger than the sum of its proper divisors (9998702).

19997398 is an equidigital number, since it uses as much as digits as its factorization.

19997398 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9998701.

The product of its digits is 1102248, while the sum is 55.

The square root of 19997398 is about 4471.8450330932. The cubic root of 19997398 is about 271.4299896246.

The spelling of 19997398 in words is "nineteen million, nine hundred ninety-seven thousand, three hundred ninety-eight".