820461813681 has 8 divisors (see below), whose sum is σ = 1123515276544. Its totient is φ = 532191446640.

The previous prime is 820461813667. The next prime is 820461813707. The reversal of 820461813681 is 186318164028.

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

It is not a de Polignac number, because 820461813681 - 2¹⁰ = 820461812657 is a prime.

It is a super-2 number, since 2×820461813681² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 820461813681.

It is not an unprimeable number, because it can be changed into a prime (820461823681) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3695773825 + ... + 3695774046.

It is an arithmetic number, because the mean of its divisors is an integer number (140439409568).

Almost surely, 2^820461813681 is an apocalyptic number.

It is an amenable number.

820461813681 is a deficient number, since it is larger than the sum of its proper divisors (303053462863).

820461813681 is a wasteful number, since it uses less digits than its factorization.

820461813681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7391547911.

The product of its (nonzero) digits is 442368, while the sum is 48.

The spelling of 820461813681 in words is "eight hundred twenty billion, four hundred sixty-one million, eight hundred thirteen thousand, six hundred eighty-one".