851669991 has 16 divisors (see below), whose sum is σ = 1274744800. Its totient is φ = 561924864.

The previous prime is 851669981. The next prime is 851669993. The reversal of 851669991 is 199966158.

It is a de Polignac number, because none of the positive numbers 2^k-851669991 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (851669993) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 159976 + ... + 165213.

It is an arithmetic number, because the mean of its divisors is an integer number (79671550).

Almost surely, 2^851669991 is an apocalyptic number.

851669991 is a deficient number, since it is larger than the sum of its proper divisors (423074809).

851669991 is a wasteful number, since it uses less digits than its factorization.

851669991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 325295 (or 325289 counting only the distinct ones).

The product of its digits is 1049760, while the sum is 54.

The square root of 851669991 is about 29183.3855301266. The cubic root of 851669991 is about 947.8881958357. Note that the first 3 decimals are identical.

The spelling of 851669991 in words is "eight hundred fifty-one million, six hundred sixty-nine thousand, nine hundred ninety-one".