851641687531 has 4 divisors (see below), whose sum is σ = 879114000064. Its totient is φ = 824169375000.

The previous prime is 851641687529. The next prime is 851641687541. The reversal of 851641687531 is 135786146158.

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 851641687531 - 2¹ = 851641687529 is a prime.

It is a super-2 number, since 2×851641687531² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (851641687541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13736156220 + ... + 13736156281.

It is an arithmetic number, because the mean of its divisors is an integer number (219778500016).

Almost surely, 2^851641687531 is an apocalyptic number.

851641687531 is a deficient number, since it is larger than the sum of its proper divisors (27472312533).

851641687531 is a wasteful number, since it uses less digits than its factorization.

851641687531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27472312532.

The product of its digits is 4838400, while the sum is 55.

The spelling of 851641687531 in words is "eight hundred fifty-one billion, six hundred forty-one million, six hundred eighty-seven thousand, five hundred thirty-one".