20215965 has 64 divisors (see below), whose sum is σ = 42135552. Its totient is φ = 8025600.

The previous prime is 20215883. The next prime is 20215967. The reversal of 20215965 is 56951202.

It is a happy number.

It is not a de Polignac number, because 20215965 - 2¹⁴ = 20199581 is a prime.

It is a Curzon number.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20215967) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 26185 + ... + 26945.

It is an arithmetic number, because the mean of its divisors is an integer number (658368).

Almost surely, 2^20215965 is an apocalyptic number.

It is an amenable number.

20215965 is an abundant number, since it is smaller than the sum of its proper divisors (21919587).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20215965 is a wasteful number, since it uses less digits than its factorization.

20215965 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 810.

The product of its (nonzero) digits is 5400, while the sum is 30.

The square root of 20215965 is about 4496.2167429963. The cubic root of 20215965 is about 272.4152978615.

The spelling of 20215965 in words is "twenty million, two hundred fifteen thousand, nine hundred sixty-five".