820553664 has 112 divisors (see below), whose sum is σ = 2541885696. Its totient is φ = 228710400.

The previous prime is 820553641. The next prime is 820553677. The reversal of 820553664 is 466355028.

It is a tau number, because it is divible by the number of its divisors (112).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 47659 + ... + 62549.

It is an arithmetic number, because the mean of its divisors is an integer number (22695408).

Almost surely, 2^820553664 is an apocalyptic number.

820553664 is a gapful number since it is divisible by the number (84) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 820553664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1270942848).

820553664 is an abundant number, since it is smaller than the sum of its proper divisors (1721332032).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

820553664 is a wasteful number, since it uses less digits than its factorization.

820553664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14954 (or 14944 counting only the distinct ones).

The product of its (nonzero) digits is 172800, while the sum is 39.

The square root of 820553664 is about 28645.3078880294. The cubic root of 820553664 is about 936.2007751052.

The spelling of 820553664 in words is "eight hundred twenty million, five hundred fifty-three thousand, six hundred sixty-four".