20865761 has 32 divisors (see below), whose sum is σ = 26611200. Its totient is φ = 15966720.

The previous prime is 20865751. The next prime is 20865769. The reversal of 20865761 is 16756802.

It is not a de Polignac number, because 20865761 - 2¹⁰ = 20864737 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20865769) 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 31 ways as a sum of consecutive naturals, for example, 191375 + ... + 191483.

It is an arithmetic number, because the mean of its divisors is an integer number (831600).

Almost surely, 2^20865761 is an apocalyptic number.

It is an amenable number.

20865761 is a deficient number, since it is larger than the sum of its proper divisors (5745439).

20865761 is a wasteful number, since it uses less digits than its factorization.

20865761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 209.

The product of its (nonzero) digits is 20160, while the sum is 35.

The square root of 20865761 is about 4567.9055375522. The cubic root of 20865761 is about 275.3032951275.

The spelling of 20865761 in words is "twenty million, eight hundred sixty-five thousand, seven hundred sixty-one".