20631161 has 4 divisors (see below), whose sum is σ = 21528192. Its totient is φ = 19734132.

The previous prime is 20631157. The next prime is 20631173. The reversal of 20631161 is 16113602.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 16113602 = 2 ⋅8056801.

It is a cyclic number.

It is not a de Polignac number, because 20631161 - 2² = 20631157 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20634161) 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, 448481 + ... + 448526.

It is an arithmetic number, because the mean of its divisors is an integer number (5382048).

Almost surely, 2^20631161 is an apocalyptic number.

It is an amenable number.

20631161 is a deficient number, since it is larger than the sum of its proper divisors (897031).

20631161 is an equidigital number, since it uses as much as digits as its factorization.

20631161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 897030.

The product of its (nonzero) digits is 216, while the sum is 20.

The square root of 20631161 is about 4542.1537842746. The cubic root of 20631161 is about 274.2676314835.

Adding to 20631161 its reverse (16113602), we get a palindrome (36744763).

The spelling of 20631161 in words is "twenty million, six hundred thirty-one thousand, one hundred sixty-one".