842721805 has 8 divisors (see below), whose sum is σ = 1038597912. Its totient is φ = 655956288.

The previous prime is 842721793. The next prime is 842721827. The reversal of 842721805 is 508127248.

842721805 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 359557444 + 483164361 = 18962^2 + 21981^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 842721805 - 2⁹ = 842721293 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2277442 + ... + 2277811.

It is an arithmetic number, because the mean of its divisors is an integer number (129824739).

Almost surely, 2^842721805 is an apocalyptic number.

It is an amenable number.

842721805 is a deficient number, since it is larger than the sum of its proper divisors (195876107).

842721805 is a wasteful number, since it uses less digits than its factorization.

842721805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4555295.

The product of its (nonzero) digits is 35840, while the sum is 37.

The square root of 842721805 is about 29029.6711142238. The cubic root of 842721805 is about 944.5567959869.

The spelling of 842721805 in words is "eight hundred forty-two million, seven hundred twenty-one thousand, eight hundred five".