19956565 has 4 divisors (see below), whose sum is σ = 23947884. Its totient is φ = 15965248.

The previous prime is 19956557. The next prime is 19956569. The reversal of 19956565 is 56565991.

It is a happy number.

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 3908529 + 16048036 = 1977^2 + 4006^2 .

It is a cyclic number.

It is not a de Polignac number, because 19956565 - 2³ = 19956557 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19956569) 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, 1995652 + ... + 1995661.

It is an arithmetic number, because the mean of its divisors is an integer number (5986971).

Almost surely, 2^19956565 is an apocalyptic number.

It is an amenable number.

19956565 is a deficient number, since it is larger than the sum of its proper divisors (3991319).

19956565 is an equidigital number, since it uses as much as digits as its factorization.

19956565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3991318.

The product of its digits is 364500, while the sum is 46.

The square root of 19956565 is about 4467.2771349000. The cubic root of 19956565 is about 271.2451180218.

The spelling of 19956565 in words is "nineteen million, nine hundred fifty-six thousand, five hundred sixty-five".