19439897 has 4 divisors (see below), whose sum is σ = 19563876. Its totient is φ = 19315920.

The previous prime is 19439887. The next prime is 19439921. The reversal of 19439897 is 79893491.

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 3671056 + 15768841 = 1916^2 + 3971^2 .

It is a cyclic number.

It is not a de Polignac number, because 19439897 - 2¹⁰ = 19438873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19439887) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 61754 + ... + 62067.

It is an arithmetic number, because the mean of its divisors is an integer number (4890969).

Almost surely, 2^19439897 is an apocalyptic number.

It is an amenable number.

19439897 is a deficient number, since it is larger than the sum of its proper divisors (123979).

19439897 is a wasteful number, since it uses less digits than its factorization.

19439897 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123978.

The product of its digits is 489888, while the sum is 50.

The square root of 19439897 is about 4409.0698565570. The cubic root of 19439897 is about 268.8838099112.

The spelling of 19439897 in words is "nineteen million, four hundred thirty-nine thousand, eight hundred ninety-seven".