19638697 has 4 divisors (see below), whose sum is σ = 21149380. Its totient is φ = 18128016.

The previous prime is 19638683. The next prime is 19638709. The reversal of 19638697 is 79683691.

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

It can be written as a sum of positive squares in 2 ways, for example, as 1838736 + 17799961 = 1356^2 + 4219^2 .

It is a cyclic number.

It is not a de Polignac number, because 19638697 - 2²³ = 11250089 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 19638697.

It is not an unprimeable number, because it can be changed into a prime (19638617) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 755322 + ... + 755347.

It is an arithmetic number, because the mean of its divisors is an integer number (5287345).

Almost surely, 2^19638697 is an apocalyptic number.

It is an amenable number.

19638697 is a deficient number, since it is larger than the sum of its proper divisors (1510683).

19638697 is a wasteful number, since it uses less digits than its factorization.

19638697 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1510682.

The product of its digits is 489888, while the sum is 49.

The square root of 19638697 is about 4431.5569498766. The cubic root of 19638697 is about 269.7972735205.

The spelling of 19638697 in words is "nineteen million, six hundred thirty-eight thousand, six hundred ninety-seven".