20661163 has 4 divisors (see below), whose sum is σ = 20766240. Its totient is φ = 20556088.

The previous prime is 20661143. The next prime is 20661191. The reversal of 20661163 is 36116602.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20661163 - 2⁵ = 20661131 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20661143) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 52243 + ... + 52636.

It is an arithmetic number, because the mean of its divisors is an integer number (5191560).

Almost surely, 2^20661163 is an apocalyptic number.

20661163 is a deficient number, since it is larger than the sum of its proper divisors (105077).

20661163 is a wasteful number, since it uses less digits than its factorization.

20661163 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105076.

The product of its (nonzero) digits is 1296, while the sum is 25.

The square root of 20661163 is about 4545.4552027272. The cubic root of 20661163 is about 274.4005144885.

Adding to 20661163 its reverse (36116602), we get a palindrome (56777765).

The spelling of 20661163 in words is "twenty million, six hundred sixty-one thousand, one hundred sixty-three".