661722 has 16 divisors (see below), whose sum is σ = 1369440. Its totient is φ = 212912.

The previous prime is 661721. The next prime is 661741. The reversal of 661722 is 227166.

It is a happy number.

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 661692 and 661701.

It is not an unprimeable number, because it can be changed into a prime (661721) 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, 1728 + ... + 2075.

It is an arithmetic number, because the mean of its divisors is an integer number (85590).

2⁶⁶¹⁷²² is an apocalyptic number.

661722 is an abundant number, since it is smaller than the sum of its proper divisors (707718).

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

661722 is a wasteful number, since it uses less digits than its factorization.

661722 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3837.

The product of its digits is 1008, while the sum is 24.

The square root of 661722 is about 813.4629678111. The cubic root of 661722 is about 87.1415320821.

Adding to 661722 its reverse (227166), we get a palindrome (888888).

The spelling of 661722 in words is "six hundred sixty-one thousand, seven hundred twenty-two".