842721 has 8 divisors (see below), whose sum is σ = 1225824. Its totient is φ = 510720.

The previous prime is 842701. The next prime is 842729. The reversal of 842721 is 127248.

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

It is not a de Polignac number, because 842721 - 2⁶ = 842657 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 842691 and 842700.

It is not an unprimeable number, because it can be changed into a prime (842729) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12736 + ... + 12801.

It is an arithmetic number, because the mean of its divisors is an integer number (153228).

2⁸⁴²⁷²¹ is an apocalyptic number.

It is an amenable number.

842721 is a deficient number, since it is larger than the sum of its proper divisors (383103).

842721 is a wasteful number, since it uses less digits than its factorization.

842721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25551.

The product of its digits is 896, while the sum is 24.

The square root of 842721 is about 917.9983660116. The cubic root of 842721 is about 94.4556495228.

Adding to 842721 its reverse (127248), we get a palindrome (969969).

It can be divided in two parts, 8427 and 21, that added together give a palindrome (8448).

The spelling of 842721 in words is "eight hundred forty-two thousand, seven hundred twenty-one".