820025778 has 128 divisors (see below), whose sum is σ = 1991485440. Its totient is φ = 221829120.

The previous prime is 820025761. The next prime is 820025813. The reversal of 820025778 is 877520028.

It is a Harshad number since it is a multiple of its sum of digits (39).

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 63 ways as a sum of consecutive naturals, for example, 4910251 + ... + 4910417.

It is an arithmetic number, because the mean of its divisors is an integer number (15558480).

Almost surely, 2^820025778 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 820025778, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (995742720).

820025778 is an abundant number, since it is smaller than the sum of its proper divisors (1171459662).

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

820025778 is a wasteful number, since it uses less digits than its factorization.

820025778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 352.

The product of its (nonzero) digits is 62720, while the sum is 39.

The square root of 820025778 is about 28636.0922264194. The cubic root of 820025778 is about 935.9999703229. Note that the first 4 decimals are identical.

The spelling of 820025778 in words is "eight hundred twenty million, twenty-five thousand, seven hundred seventy-eight".