820781842 has 8 divisors (see below), whose sum is σ = 1233593100. Its totient is φ = 409584144.

The previous prime is 820781827. The next prime is 820781891. The reversal of 820781842 is 248187028.

It can be written as a sum of positive squares in 2 ways, for example, as 820765201 + 16641 = 28649^2 + 129^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 820781795 and 820781804.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 402117 + ... + 404152.

Almost surely, 2^820781842 is an apocalyptic number.

820781842 is a deficient number, since it is larger than the sum of its proper divisors (412811258).

820781842 is a wasteful number, since it uses less digits than its factorization.

820781842 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 806780.

The product of its (nonzero) digits is 57344, while the sum is 40.

The square root of 820781842 is about 28649.2904275132. The cubic root of 820781842 is about 936.2875460388.

The spelling of 820781842 in words is "eight hundred twenty million, seven hundred eighty-one thousand, eight hundred forty-two".