660343621 has 16 divisors (see below), whose sum is σ = 763551360. Its totient is φ = 559391040.

The previous prime is 660343591. The next prime is 660343643. The reversal of 660343621 is 126343066.

It is a cyclic number.

It is not a de Polignac number, because 660343621 - 2⁹ = 660343109 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (660343661) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 245335 + ... + 248011.

It is an arithmetic number, because the mean of its divisors is an integer number (47721960).

Almost surely, 2^660343621 is an apocalyptic number.

It is an amenable number.

660343621 is a deficient number, since it is larger than the sum of its proper divisors (103207739).

660343621 is a wasteful number, since it uses less digits than its factorization.

660343621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3084.

The product of its (nonzero) digits is 15552, while the sum is 31.

The square root of 660343621 is about 25697.1520017297. The cubic root of 660343621 is about 870.8098422138.

Adding to 660343621 its reverse (126343066), we get a palindrome (786686687).

The spelling of 660343621 in words is "six hundred sixty million, three hundred forty-three thousand, six hundred twenty-one".