661630 has 16 divisors (see below), whose sum is σ = 1203840. Its totient is φ = 261792.

The previous prime is 661621. The next prime is 661663. The reversal of 661630 is 36166.

661630 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

661630 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, 787 + ... + 1393.

It is an arithmetic number, because the mean of its divisors is an integer number (75240).

2⁶⁶¹⁶³⁰ is an apocalyptic number.

661630 is a deficient number, since it is larger than the sum of its proper divisors (542210).

661630 is a wasteful number, since it uses less digits than its factorization.

661630 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 723.

The product of its (nonzero) digits is 648, while the sum is 22.

The square root of 661630 is about 813.4064174814. The cubic root of 661630 is about 87.1374934311.

Adding to 661630 its reverse (36166), we get a palindrome (697796).

The spelling of 661630 in words is "six hundred sixty-one thousand, six hundred thirty".