20990965 has 8 divisors (see below), whose sum is σ = 25217208. Its totient is φ = 16774080.

The previous prime is 20990947. The next prime is 20990969. The reversal of 20990965 is 56909902.

It can be written as a sum of positive squares in 4 ways, for example, as 361201 + 20629764 = 601^2 + 4542^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20990965 - 2⁵ = 20990933 is a prime.

It is a super-2 number, since 2×20990965² = 881241223262450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20990969) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4335 + ... + 7795.

It is an arithmetic number, because the mean of its divisors is an integer number (3152151).

Almost surely, 2^20990965 is an apocalyptic number.

It is an amenable number.

20990965 is a deficient number, since it is larger than the sum of its proper divisors (4226243).

20990965 is a wasteful number, since it uses less digits than its factorization.

20990965 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4679.

The product of its (nonzero) digits is 43740, while the sum is 40.

The square root of 20990965 is about 4581.5897895818. The cubic root of 20990965 is about 275.8528454863.

The spelling of 20990965 in words is "twenty million, nine hundred ninety thousand, nine hundred sixty-five".