20688361 has 8 divisors (see below), whose sum is σ = 20936264. Its totient is φ = 20442240.

The previous prime is 20688341. The next prime is 20688433. The reversal of 20688361 is 16388602.

It can be written as a sum of positive squares in 4 ways, for example, as 3515625 + 17172736 = 1875^2 + 4144^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 20688361 - 2⁵ = 20688329 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20688301) 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, 48931 + ... + 49351.

It is an arithmetic number, because the mean of its divisors is an integer number (2617033).

Almost surely, 2^20688361 is an apocalyptic number.

It is an amenable number.

20688361 is a deficient number, since it is larger than the sum of its proper divisors (247903).

20688361 is a wasteful number, since it uses less digits than its factorization.

20688361 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 891.

The product of its (nonzero) digits is 13824, while the sum is 34.

The square root of 20688361 is about 4548.4459983603. The cubic root of 20688361 is about 274.5208670682.

The spelling of 20688361 in words is "twenty million, six hundred eighty-eight thousand, three hundred sixty-one".