655165781 has 2 divisors, whose sum is σ = 655165782. Its totient is φ = 655165780.

The previous prime is 655165739. The next prime is 655165789. The reversal of 655165781 is 187561556.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 436392100 + 218773681 = 20890^2 + 14791^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-655165781 is a prime.

It is a super-2 number, since 2×655165781² = 858484401186679922, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (655165789) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 327582890 + 327582891.

It is an arithmetic number, because the mean of its divisors is an integer number (327582891).

Almost surely, 2^655165781 is an apocalyptic number.

It is an amenable number.

655165781 is a deficient number, since it is larger than the sum of its proper divisors (1).

655165781 is an equidigital number, since it uses as much as digits as its factorization.

655165781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 252000, while the sum is 44.

The square root of 655165781 is about 25596.2063790711. The cubic root of 655165781 is about 868.5278229285.

The spelling of 655165781 in words is "six hundred fifty-five million, one hundred sixty-five thousand, seven hundred eighty-one".