20765231 has 2 divisors, whose sum is σ = 20765232. Its totient is φ = 20765230.

The previous prime is 20765207. The next prime is 20765237. The reversal of 20765231 is 13256702.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20765231 is a prime.

It is a super-2 number, since 2×20765231² = 862389636966722, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20765231.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20765237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10382615 + 10382616.

It is an arithmetic number, because the mean of its divisors is an integer number (10382616).

Almost surely, 2^20765231 is an apocalyptic number.

20765231 is a deficient number, since it is larger than the sum of its proper divisors (1).

20765231 is an equidigital number, since it uses as much as digits as its factorization.

20765231 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2520, while the sum is 26.

The square root of 20765231 is about 4556.8883023397. Note that the first 3 decimals coincide. The cubic root of 20765231 is about 274.8604515123.

The spelling of 20765231 in words is "twenty million, seven hundred sixty-five thousand, two hundred thirty-one".