819741978 has 64 divisors (see below), whose sum is σ = 1991485440. Its totient is φ = 247878000.

The previous prime is 819741977. The next prime is 819741983. The reversal of 819741978 is 879147918.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (819741971) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 347503 + ... + 349853.

It is an arithmetic number, because the mean of its divisors is an integer number (31116960).

Almost surely, 2^819741978 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 819741978, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (995742720).

819741978 is an abundant number, since it is smaller than the sum of its proper divisors (1171743462).

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

819741978 is a wasteful number, since it uses less digits than its factorization.

819741978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2960 (or 2954 counting only the distinct ones).

The product of its digits is 1016064, while the sum is 54.

The square root of 819741978 is about 28631.1365125452. The cubic root of 819741978 is about 935.8919788227.

The spelling of 819741978 in words is "eight hundred nineteen million, seven hundred forty-one thousand, nine hundred seventy-eight".