851240 has 32 divisors (see below), whose sum is σ = 2063880. Its totient is φ = 314112.

The previous prime is 851239. The next prime is 851251. The reversal of 851240 is 42158.

It can be written as a sum of positive squares in 4 ways, for example, as 276676 + 574564 = 526^2 + 758^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

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 7 ways as a sum of consecutive naturals, for example, 299 + ... + 1338.

2⁸⁵¹²⁴⁰ is an apocalyptic number.

It is an amenable number.

851240 is an abundant number, since it is smaller than the sum of its proper divisors (1212640).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

851240 is a wasteful number, since it uses less digits than its factorization.

851240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1661 (or 1657 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 20.

The square root of 851240 is about 922.6266850682. The cubic root of 851240 is about 94.7728645771.

Adding to 851240 its reverse (42158), we get a palindrome (893398).

The spelling of 851240 in words is "eight hundred fifty-one thousand, two hundred forty".