19997603 has 4 divisors (see below), whose sum is σ = 20867088. Its totient is φ = 19128120.

The previous prime is 19997599. The next prime is 19997609. The reversal of 19997603 is 30679991.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 30679991 = 89 ⋅344719.

It is a cyclic number.

It is not a de Polignac number, because 19997603 - 2² = 19997599 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19997609) 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 in 3 ways as a sum of consecutive naturals, for example, 434708 + ... + 434753.

It is an arithmetic number, because the mean of its divisors is an integer number (5216772).

Almost surely, 2^19997603 is an apocalyptic number.

19997603 is a deficient number, since it is larger than the sum of its proper divisors (869485).

19997603 is an equidigital number, since it uses as much as digits as its factorization.

19997603 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 869484.

The product of its (nonzero) digits is 91854, while the sum is 44.

The square root of 19997603 is about 4471.8679542223. The cubic root of 19997603 is about 271.4309171279.

The spelling of 19997603 in words is "nineteen million, nine hundred ninety-seven thousand, six hundred three".