820645042 has 24 divisors (see below), whose sum is σ = 1456222320. Its totient is φ = 345741480.

The previous prime is 820645009. The next prime is 820645069. The reversal of 820645042 is 240546028.

It is a junction number, because it is equal to n+sod(n) for n = 820644995 and 820645013.

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 11 ways as a sum of consecutive naturals, for example, 65184 + ... + 76747.

It is an arithmetic number, because the mean of its divisors is an integer number (60675930).

Almost surely, 2^820645042 is an apocalyptic number.

820645042 is a deficient number, since it is larger than the sum of its proper divisors (635577278).

820645042 is a wasteful number, since it uses less digits than its factorization.

820645042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 142006 (or 141999 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 31.

The square root of 820645042 is about 28646.9028343380. The cubic root of 820645042 is about 936.2355260231.

The spelling of 820645042 in words is "eight hundred twenty million, six hundred forty-five thousand, forty-two".