810168721551 has 24 divisors (see below), whose sum is σ = 1407811982720. Its totient is φ = 438587577936.

The previous prime is 810168721547. The next prime is 810168721597. The reversal of 810168721551 is 155127861018.

810168721551 is a `hidden beast` number, since 8 + 1 + 0 + 16 + 87 + 2 + 1 + 551 = 666.

It is not a de Polignac number, because 810168721551 - 2² = 810168721547 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 810168721497 and 810168721506.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (810168721651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 338415145 + ... + 338417538.

Almost surely, 2^810168721551 is an apocalyptic number.

810168721551 is a deficient number, since it is larger than the sum of its proper divisors (597643261169).

810168721551 is a wasteful number, since it uses less digits than its factorization.

810168721551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 676832715 (or 676832712 counting only the distinct ones).

The product of its (nonzero) digits is 134400, while the sum is 45.

The spelling of 810168721551 in words is "eight hundred ten billion, one hundred sixty-eight million, seven hundred twenty-one thousand, five hundred fifty-one".