19785397 has 4 divisors (see below), whose sum is σ = 19837440. Its totient is φ = 19733356.

The previous prime is 19785391. The next prime is 19785401. The reversal of 19785397 is 79358791.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19785397 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 19785397.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19785391) 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, 25447 + ... + 26212.

It is an arithmetic number, because the mean of its divisors is an integer number (4959360).

Almost surely, 2^19785397 is an apocalyptic number.

It is an amenable number.

19785397 is a deficient number, since it is larger than the sum of its proper divisors (52043).

19785397 is an equidigital number, since it uses as much as digits as its factorization.

19785397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52042.

The product of its digits is 476280, while the sum is 49.

The square root of 19785397 is about 4448.0778994977. The cubic root of 19785397 is about 270.4673980090.

The spelling of 19785397 in words is "nineteen million, seven hundred eighty-five thousand, three hundred ninety-seven".