721842 has 16 divisors (see below), whose sum is σ = 1575072. Its totient is φ = 218720.

The previous prime is 721793. The next prime is 721843. The reversal of 721842 is 248127.

It is not an unprimeable number, because it can be changed into a prime (721843) by changing a digit.

721842 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5403 + ... + 5534.

It is an arithmetic number, because the mean of its divisors is an integer number (98442).

2⁷²¹⁸⁴² is an apocalyptic number.

721842 is an abundant number, since it is smaller than the sum of its proper divisors (853230).

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

721842 is a wasteful number, since it uses less digits than its factorization.

721842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10953.

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

The square root of 721842 is about 849.6128530101. The cubic root of 721842 is about 89.7044626910.

Adding to 721842 its reverse (248127), we get a palindrome (969969).

It can be divided in two parts, 7218 and 42, that added together give a triangular number (7260 = T₁₂₀).

The spelling of 721842 in words is "seven hundred twenty-one thousand, eight hundred forty-two".