20641231 has 4 divisors (see below), whose sum is σ = 22229032. Its totient is φ = 19053432.

The previous prime is 20641223. The next prime is 20641253. The reversal of 20641231 is 13214602.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13214602 = 2 ⋅6607301.

It is a cyclic number.

It is not a de Polignac number, because 20641231 - 2³ = 20641223 is a prime.

It is a super-2 number, since 2×20641231² = 852120834390722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20641199 and 20641208.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20641211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 793881 + ... + 793906.

It is an arithmetic number, because the mean of its divisors is an integer number (5557258).

Almost surely, 2^20641231 is an apocalyptic number.

20641231 is a deficient number, since it is larger than the sum of its proper divisors (1587801).

20641231 is a wasteful number, since it uses less digits than its factorization.

20641231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1587800.

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 20641231 is about 4543.2621540034. The cubic root of 20641231 is about 274.3122472602.

Adding to 20641231 its reverse (13214602), we get a palindrome (33855833).

The spelling of 20641231 in words is "twenty million, six hundred forty-one thousand, two hundred thirty-one".