851008357861 has 4 divisors (see below), whose sum is σ = 856719823500. Its totient is φ = 845296892224.

The previous prime is 851008357847. The next prime is 851008357867. The reversal of 851008357861 is 168753800158.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 210136060836 + 640872297025 = 458406^2 + 800545^2 .

It is a cyclic number.

It is not a de Polignac number, because 851008357861 - 2⁷ = 851008357733 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 851008357799 and 851008357808.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (851008357867) 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, 2855732596 + ... + 2855732893.

It is an arithmetic number, because the mean of its divisors is an integer number (214179955875).

Almost surely, 2^851008357861 is an apocalyptic number.

It is an amenable number.

851008357861 is a deficient number, since it is larger than the sum of its proper divisors (5711465639).

851008357861 is a wasteful number, since it uses less digits than its factorization.

851008357861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5711465638.

The product of its (nonzero) digits is 1612800, while the sum is 52.

The spelling of 851008357861 in words is "eight hundred fifty-one billion, eight million, three hundred fifty-seven thousand, eight hundred sixty-one".