661610 has 8 divisors (see below), whose sum is σ = 1190916. Its totient is φ = 264640.

The previous prime is 661607. The next prime is 661613. The reversal of 661610 is 16166.

It is an interprime number because it is at equal distance from previous prime (661607) and next prime (661613).

It can be written as a sum of positive squares in 2 ways, for example, as 628849 + 32761 = 793^2 + 181^2 .

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

It is an Ulam number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (661613) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33071 + ... + 33090.

2⁶⁶¹⁶¹⁰ is an apocalyptic number.

661610 is a deficient number, since it is larger than the sum of its proper divisors (529306).

661610 is a wasteful number, since it uses less digits than its factorization.

661610 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66168.

The product of its (nonzero) digits is 216, while the sum is 20.

The square root of 661610 is about 813.3941234113. The cubic root of 661610 is about 87.1366154140.

Adding to 661610 its reverse (16166), we get a palindrome (677776).

It can be divided in two parts, 6 and 61610, that added together give a palindrome (61616).

The spelling of 661610 in words is "six hundred sixty-one thousand, six hundred ten".