820545840 has 120 divisors (see below), whose sum is σ = 2763232368. Its totient is φ = 218211840.

The previous prime is 820545839. The next prime is 820545853. The reversal of 820545840 is 48545028.

820545840 is a `hidden beast` number, since 8 + 20 + 54 + 584 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 820545795 and 820545804.

It is an unprimeable number.

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 in 23 ways as a sum of consecutive naturals, for example, 301767 + ... + 304473.

Almost surely, 2^820545840 is an apocalyptic number.

820545840 is a gapful number since it is divisible by the number (80) 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 820545840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1381616184).

820545840 is an abundant number, since it is smaller than the sum of its proper divisors (1942686528).

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

820545840 is a wasteful number, since it uses less digits than its factorization.

820545840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3147 (or 3138 counting only the distinct ones).

The product of its (nonzero) digits is 51200, while the sum is 36.

The square root of 820545840 is about 28645.1713208352. The cubic root of 820545840 is about 936.1977995297.

It can be divided in two parts, 8205 and 45840, that added together give a palindrome (54045).

The spelling of 820545840 in words is "eight hundred twenty million, five hundred forty-five thousand, eight hundred forty".