851641665 has 16 divisors (see below), whose sum is σ = 1557287808. Its totient is φ = 389321856.

The previous prime is 851641613. The next prime is 851641697. The reversal of 851641665 is 566146158.

It is not a de Polignac number, because 851641665 - 2¹¹ = 851639617 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4055332 + ... + 4055541.

It is an arithmetic number, because the mean of its divisors is an integer number (97330488).

Almost surely, 2^851641665 is an apocalyptic number.

It is an amenable number.

851641665 is a deficient number, since it is larger than the sum of its proper divisors (705646143).

851641665 is a wasteful number, since it uses less digits than its factorization.

851641665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8110888.

The product of its digits is 172800, while the sum is 42.

The square root of 851641665 is about 29182.9002157085. The cubic root of 851641665 is about 947.8776870005.

The spelling of 851641665 in words is "eight hundred fifty-one million, six hundred forty-one thousand, six hundred sixty-five".