51821167865645 has 8 divisors (see below), whose sum is σ = 62185890923640. Its totient is φ = 41456607969280.

The previous prime is 51821167865627. The next prime is 51821167865693. The reversal of 51821167865645 is 54656876112815.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1543113012841 + 50278054852804 = 1242221^2 + 7090702^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 51821167865645 - 2³⁶ = 51752448388909 is a prime.

It is a super-3 number, since 3×51821167865645³ (a number of 42 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40090580 + ... + 41362989.

It is an arithmetic number, because the mean of its divisors is an integer number (7773236365455).

Almost surely, 2^{51821167865645} is an apocalyptic number.

It is an amenable number.

51821167865645 is a deficient number, since it is larger than the sum of its proper divisors (10364723057995).

51821167865645 is a wasteful number, since it uses less digits than its factorization.

51821167865645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81580815.

The product of its digits is 96768000, while the sum is 65.

The spelling of 51821167865645 in words is "fifty-one trillion, eight hundred twenty-one billion, one hundred sixty-seven million, eight hundred sixty-five thousand, six hundred forty-five".