51840917857 has 4 divisors (see below), whose sum is σ = 51881451520. Its totient is φ = 51800384196.

The previous prime is 51840917833. The next prime is 51840917861. The reversal of 51840917857 is 75871904815.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 51840917857 - 2³¹ = 49693434209 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 51840917798 and 51840917807.

It is not an unprimeable number, because it can be changed into a prime (51840917867) 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, 20264913 + ... + 20267470.

It is an arithmetic number, because the mean of its divisors is an integer number (12970362880).

Almost surely, 2^51840917857 is an apocalyptic number.

It is an amenable number.

51840917857 is a deficient number, since it is larger than the sum of its proper divisors (40533663).

51840917857 is a wasteful number, since it uses less digits than its factorization.

51840917857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40533662.

The product of its (nonzero) digits is 2822400, while the sum is 55.

The spelling of 51840917857 in words is "fifty-one billion, eight hundred forty million, nine hundred seventeen thousand, eight hundred fifty-seven".