851551 has 4 divisors (see below), whose sum is σ = 867672. Its totient is φ = 835432.

The previous prime is 851549. The next prime is 851569. The reversal of 851551 is 155158.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 851551 - 2¹ = 851549 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 (851051) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7981 + ... + 8086.

It is an arithmetic number, because the mean of its divisors is an integer number (216918).

2⁸⁵¹⁵⁵¹ is an apocalyptic number.

851551 is a deficient number, since it is larger than the sum of its proper divisors (16121).

851551 is a wasteful number, since it uses less digits than its factorization.

851551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16120.

The product of its digits is 1000, while the sum is 25.

The square root of 851551 is about 922.7952102173. The cubic root of 851551 is about 94.7844049074.

The spelling of 851551 in words is "eight hundred fifty-one thousand, five hundred fifty-one".