661710 has 64 divisors (see below), whose sum is σ = 1907712. Its totient is φ = 143616.

The previous prime is 661697. The next prime is 661721. The reversal of 661710 is 17166.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is an unprimeable number.

661710 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 31 ways as a sum of consecutive naturals, for example, 4762 + ... + 4898.

It is an arithmetic number, because the mean of its divisors is an integer number (29808).

2⁶⁶¹⁷¹⁰ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661710, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (953856).

661710 is an abundant number, since it is smaller than the sum of its proper divisors (1246002).

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

661710 is a wasteful number, since it uses less digits than its factorization.

661710 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 177.

The product of its (nonzero) digits is 252, while the sum is 21.

The square root of 661710 is about 813.4555919041. The cubic root of 661710 is about 87.1410053228.

Adding to 661710 its reverse (17166), we get a palindrome (678876).

It can be divided in two parts, 6 and 61710, that added together give a palindrome (61716).

The spelling of 661710 in words is "six hundred sixty-one thousand, seven hundred ten".