19663965 has 40 divisors (see below), whose sum is σ = 36799488. Its totient is φ = 10026720.

The previous prime is 19663961. The next prime is 19663967. The reversal of 19663965 is 56936691.

19663965 is a `hidden beast` number, since 1 + 9 + 6 + 639 + 6 + 5 = 666.

It is not a de Polignac number, because 19663965 - 2² = 19663961 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 19663965.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19663961) 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 39 ways as a sum of consecutive naturals, for example, 8260 + ... + 10370.

Almost surely, 2^19663965 is an apocalyptic number.

19663965 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

19663965 is a deficient number, since it is larger than the sum of its proper divisors (17135523).

19663965 is a wasteful number, since it uses less digits than its factorization.

19663965 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2151 (or 2142 counting only the distinct ones).

The product of its digits is 262440, while the sum is 45.

The square root of 19663965 is about 4434.4069502020. The cubic root of 19663965 is about 269.9129348907.

The spelling of 19663965 in words is "nineteen million, six hundred sixty-three thousand, nine hundred sixty-five".