820644450645 has 16 divisors (see below), whose sum is σ = 1358308056960. Its totient is φ = 422584728384.

The previous prime is 820644450641. The next prime is 820644450697. The reversal of 820644450645 is 546054446028.

It is not a de Polignac number, because 820644450645 - 2² = 820644450641 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 820644450594 and 820644450603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (820644450641) 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 15 ways as a sum of consecutive naturals, for example, 943269049 + ... + 943269918.

It is an arithmetic number, because the mean of its divisors is an integer number (84894253560).

Almost surely, 2^820644450645 is an apocalyptic number.

It is an amenable number.

820644450645 is a deficient number, since it is larger than the sum of its proper divisors (537663606315).

820644450645 is a wasteful number, since it uses less digits than its factorization.

820644450645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1886539004.

The product of its (nonzero) digits is 3686400, while the sum is 48.

The spelling of 820644450645 in words is "eight hundred twenty billion, six hundred forty-four million, four hundred fifty thousand, six hundred forty-five".