821742 has 16 divisors (see below), whose sum is σ = 1656192. Its totient is φ = 271800.

The previous prime is 821741. The next prime is 821747. The reversal of 821742 is 247128.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 453 + ... + 1359.

It is an arithmetic number, because the mean of its divisors is an integer number (103512).

2⁸²¹⁷⁴² is an apocalyptic number.

It is a pronic number, being equal to 906×907.

821742 is an abundant number, since it is smaller than the sum of its proper divisors (834450).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

821742 is a wasteful number, since it uses less digits than its factorization.

821742 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1063.

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

The square root of 821742 is about 906.4998621070. The cubic root of 821742 is about 93.6652496306.

The spelling of 821742 in words is "eight hundred twenty-one thousand, seven hundred forty-two".