19997455 has 4 divisors (see below), whose sum is σ = 23996952. Its totient is φ = 15997960.

The previous prime is 19997441. The next prime is 19997459. The reversal of 19997455 is 55479991.

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

It is not a de Polignac number, because 19997455 - 2²³ = 11608847 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 19997399 and 19997408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19997459) 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, 1999741 + ... + 1999750.

It is an arithmetic number, because the mean of its divisors is an integer number (5999238).

Almost surely, 2^19997455 is an apocalyptic number.

19997455 is a deficient number, since it is larger than the sum of its proper divisors (3999497).

19997455 is an equidigital number, since it uses as much as digits as its factorization.

19997455 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3999496.

The product of its digits is 510300, while the sum is 49.

The square root of 19997455 is about 4471.8514062969. The cubic root of 19997455 is about 271.4302475164.

The spelling of 19997455 in words is "nineteen million, nine hundred ninety-seven thousand, four hundred fifty-five".