20665965 has 16 divisors (see below), whose sum is σ = 35011008. Its totient is φ = 10373376.

The previous prime is 20665963. The next prime is 20665969. The reversal of 20665965 is 56956602.

It is not a de Polignac number, because 20665965 - 2¹ = 20665963 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20665961) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 40267 + ... + 40776.

It is an arithmetic number, because the mean of its divisors is an integer number (2188188).

Almost surely, 2^20665965 is an apocalyptic number.

It is an amenable number.

20665965 is a deficient number, since it is larger than the sum of its proper divisors (14345043).

20665965 is a wasteful number, since it uses less digits than its factorization.

20665965 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81068.

The product of its (nonzero) digits is 97200, while the sum is 39.

The square root of 20665965 is about 4545.9833919626. The cubic root of 20665965 is about 274.4217712654.

The spelling of 20665965 in words is "twenty million, six hundred sixty-five thousand, nine hundred sixty-five".