820678706649 has 24 divisors (see below), whose sum is σ = 1199781894792. Its totient is φ = 540516499200.

The previous prime is 820678706593. The next prime is 820678706657. The reversal of 820678706649 is 946607876028.

820678706649 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 309892622400 + 510786084249 = 556680^2 + 714693^2 .

It is not a de Polignac number, because 820678706649 - 2⁹ = 820678706137 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (820678706249) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 572374 + ... + 1403199.

It is an arithmetic number, because the mean of its divisors is an integer number (49990912283).

Almost surely, 2^820678706649 is an apocalyptic number.

It is an amenable number.

820678706649 is a deficient number, since it is larger than the sum of its proper divisors (379103188143).

820678706649 is a wasteful number, since it uses less digits than its factorization.

820678706649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1976137 (or 1976134 counting only the distinct ones).

The product of its (nonzero) digits is 48771072, while the sum is 63.

The spelling of 820678706649 in words is "eight hundred twenty billion, six hundred seventy-eight million, seven hundred six thousand, six hundred forty-nine".