905166721 has 2 divisors, whose sum is σ = 905166722. Its totient is φ = 905166720.

The previous prime is 905166677. The next prime is 905166733. The reversal of 905166721 is 127661509.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 844716096 + 60450625 = 29064^2 + 7775^2 .

It is a cyclic number.

It is not a de Polignac number, because 905166721 - 2¹⁹ = 904642433 is a prime.

It is not a weakly prime, because it can be changed into another prime (905166761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 452583360 + 452583361.

It is an arithmetic number, because the mean of its divisors is an integer number (452583361).

Almost surely, 2^905166721 is an apocalyptic number.

It is an amenable number.

905166721 is a deficient number, since it is larger than the sum of its proper divisors (1).

905166721 is an equidigital number, since it uses as much as digits as its factorization.

905166721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 22680, while the sum is 37.

The square root of 905166721 is about 30085.9887821557. The cubic root of 905166721 is about 967.3334211894. Note that the first 3 decimals are identical.

The spelling of 905166721 in words is "nine hundred five million, one hundred sixty-six thousand, seven hundred twenty-one".