820777064 has 8 divisors (see below), whose sum is σ = 1538957010. Its totient is φ = 410388528.

The previous prime is 820777063. The next prime is 820777093. The reversal of 820777064 is 460777028.

It can be written as a sum of positive squares in only one way, i.e., 736688164 + 84088900 = 27142^2 + 9170^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (820777063) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 51298559 + ... + 51298574.

Almost surely, 2^820777064 is an apocalyptic number.

It is an amenable number.

820777064 is a deficient number, since it is larger than the sum of its proper divisors (718179946).

820777064 is a wasteful number, since it uses less digits than its factorization.

820777064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102597139 (or 102597135 counting only the distinct ones).

The product of its (nonzero) digits is 131712, while the sum is 41.

The square root of 820777064 is about 28649.2070396372. The cubic root of 820777064 is about 936.2857292383.

The spelling of 820777064 in words is "eight hundred twenty million, seven hundred seventy-seven thousand, sixty-four".