20688265 has 8 divisors (see below), whose sum is σ = 26735688. Its totient is φ = 15277440.

The previous prime is 20688263. The next prime is 20688277. The reversal of 20688265 is 56288602.

It can be written as a sum of positive squares in 4 ways, for example, as 1089936 + 19598329 = 1044^2 + 4427^2 .

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

It is not a de Polignac number, because 20688265 - 2¹ = 20688263 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20688263) 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, 159076 + ... + 159205.

It is an arithmetic number, because the mean of its divisors is an integer number (3341961).

Almost surely, 2^20688265 is an apocalyptic number.

It is an amenable number.

20688265 is a deficient number, since it is larger than the sum of its proper divisors (6047423).

20688265 is a wasteful number, since it uses less digits than its factorization.

20688265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 318299.

The product of its (nonzero) digits is 46080, while the sum is 37.

The square root of 20688265 is about 4548.4354452932. The cubic root of 20688265 is about 274.5204424487.

The spelling of 20688265 in words is "twenty million, six hundred eighty-eight thousand, two hundred sixty-five".