19959965 has 4 divisors (see below), whose sum is σ = 23951964. Its totient is φ = 15967968.

The previous prime is 19959949. The next prime is 19959977. The reversal of 19959965 is 56995991.

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 6017209 + 13942756 = 2453^2 + 3734^2 .

It is a cyclic number.

It is not a de Polignac number, because 19959965 - 2⁴ = 19959949 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1995992 + ... + 1996001.

It is an arithmetic number, because the mean of its divisors is an integer number (5987991).

Almost surely, 2^19959965 is an apocalyptic number.

It is an amenable number.

19959965 is a deficient number, since it is larger than the sum of its proper divisors (3991999).

19959965 is an equidigital number, since it uses as much as digits as its factorization.

19959965 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3991998.

The product of its digits is 984150, while the sum is 53.

The square root of 19959965 is about 4467.6576636981. The cubic root of 19959965 is about 271.2605211574.

The spelling of 19959965 in words is "nineteen million, nine hundred fifty-nine thousand, nine hundred sixty-five".