851631 has 16 divisors (see below), whose sum is σ = 1254528. Its totient is φ = 509600.

The previous prime is 851623. The next prime is 851633. The reversal of 851631 is 136158.

It is a cyclic number.

It is not a de Polignac number, because 851631 - 2³ = 851623 is a prime.

It is a super-2 number, since 2×851631² = 1450550720322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (851633) 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, 4225 + ... + 4421.

It is an arithmetic number, because the mean of its divisors is an integer number (78408).

2⁸⁵¹⁶³¹ is an apocalyptic number.

851631 is a deficient number, since it is larger than the sum of its proper divisors (402897).

851631 is a wasteful number, since it uses less digits than its factorization.

851631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 342.

The product of its digits is 720, while the sum is 24.

The square root of 851631 is about 922.8385557615. The cubic root of 851631 is about 94.7873730267.

Adding to 851631 its reverse (136158), we get a palindrome (987789).

The spelling of 851631 in words is "eight hundred fifty-one thousand, six hundred thirty-one".