660621 has 12 divisors (see below), whose sum is σ = 954528. Its totient is φ = 406224.

The previous prime is 660619. The next prime is 660643. The reversal of 660621 is 126066.

It is not a de Polignac number, because 660621 - 2¹ = 660619 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (660601) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 145 + ... + 1158.

It is an arithmetic number, because the mean of its divisors is an integer number (79544).

2⁶⁶⁰⁶²¹ is an apocalyptic number.

It is an amenable number.

660621 is a deficient number, since it is larger than the sum of its proper divisors (293907).

660621 is a wasteful number, since it uses less digits than its factorization.

660621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1332 (or 1319 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 21.

The square root of 660621 is about 812.7859496817. The cubic root of 660621 is about 87.0931753768.

Adding to 660621 its reverse (126066), we get a palindrome (786687).

The spelling of 660621 in words is "six hundred sixty thousand, six hundred twenty-one".