20611231 has 2 divisors, whose sum is σ = 20611232. Its totient is φ = 20611230.

The previous prime is 20611193. The next prime is 20611273. The reversal of 20611231 is 13211602.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20611231 - 2⁹ = 20610719 is a prime.

It is a super-2 number, since 2×20611231² = 849645686670722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20611291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10305615 + 10305616.

It is an arithmetic number, because the mean of its divisors is an integer number (10305616).

Almost surely, 2^20611231 is an apocalyptic number.

20611231 is a deficient number, since it is larger than the sum of its proper divisors (1).

20611231 is an equidigital number, since it uses as much as digits as its factorization.

20611231 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 20611231 is about 4539.9593610516. The cubic root of 20611231 is about 274.1792875302.

Adding to 20611231 its reverse (13211602), we get a palindrome (33822833).

The spelling of 20611231 in words is "twenty million, six hundred eleven thousand, two hundred thirty-one".