842864021 has 4 divisors (see below), whose sum is σ = 842983500. Its totient is φ = 842744544.

The previous prime is 842863993. The next prime is 842864039. The reversal of 842864021 is 120468248.

842864021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 90459121 + 752404900 = 9511^2 + 27430^2 .

It is a cyclic number.

It is not a de Polignac number, because 842864021 - 2¹⁴ = 842847637 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (842864081) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 48446 + ... + 63503.

It is an arithmetic number, because the mean of its divisors is an integer number (210745875).

Almost surely, 2^842864021 is an apocalyptic number.

It is an amenable number.

842864021 is a deficient number, since it is larger than the sum of its proper divisors (119479).

842864021 is a wasteful number, since it uses less digits than its factorization.

842864021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 119478.

The product of its (nonzero) digits is 24576, while the sum is 35.

The square root of 842864021 is about 29032.1205047100. The cubic root of 842864021 is about 944.6099268195.

The spelling of 842864021 in words is "eight hundred forty-two million, eight hundred sixty-four thousand, twenty-one".