820739947689 has 48 divisors (see below), whose sum is σ = 1215389410560. Its totient is φ = 533534571360.

The previous prime is 820739947663. The next prime is 820739947691. The reversal of 820739947689 is 986749937028.

820739947689 is a `hidden beast` number, since 8 + 2 + 0 + 73 + 9 + 9 + 476 + 89 = 666.

It is not a de Polignac number, because 820739947689 - 2³³ = 812150013097 is a prime.

It is a super-2 number, since 2×820739947689² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (820739947609) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 45258154 + ... + 45276284.

It is an arithmetic number, because the mean of its divisors is an integer number (25320612720).

Almost surely, 2^820739947689 is an apocalyptic number.

It is an amenable number.

820739947689 is a deficient number, since it is larger than the sum of its proper divisors (394649462871).

820739947689 is a wasteful number, since it uses less digits than its factorization.

820739947689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18882 (or 18879 counting only the distinct ones).

The product of its (nonzero) digits is 329204736, while the sum is 72.

The spelling of 820739947689 in words is "eight hundred twenty billion, seven hundred thirty-nine million, nine hundred forty-seven thousand, six hundred eighty-nine".