845625721 has 2 divisors, whose sum is σ = 845625722. Its totient is φ = 845625720.

The previous prime is 845625643. The next prime is 845625769. The reversal of 845625721 is 127526548.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 780420096 + 65205625 = 27936^2 + 8075^2 .

It is a cyclic number.

It is not a de Polignac number, because 845625721 - 2¹⁷ = 845494649 is a prime.

It is not a weakly prime, because it can be changed into another prime (845625421) 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 as a sum of consecutive naturals, namely, 422812860 + 422812861.

It is an arithmetic number, because the mean of its divisors is an integer number (422812861).

Almost surely, 2^845625721 is an apocalyptic number.

It is an amenable number.

845625721 is a deficient number, since it is larger than the sum of its proper divisors (1).

845625721 is an equidigital number, since it uses as much as digits as its factorization.

845625721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 134400, while the sum is 40.

The square root of 845625721 is about 29079.6444441812. The cubic root of 845625721 is about 945.6404944715.

The spelling of 845625721 in words is "eight hundred forty-five million, six hundred twenty-five thousand, seven hundred twenty-one".