660340421 has 16 divisors (see below), whose sum is σ = 755462400. Its totient is φ = 572142528.

The previous prime is 660340403. The next prime is 660340427. The reversal of 660340421 is 124043066.

It is a cyclic number.

It is not a de Polignac number, because 660340421 - 2⁶ = 660340357 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 (660340427) 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, 14660 + ... + 39186.

It is an arithmetic number, because the mean of its divisors is an integer number (47216400).

Almost surely, 2^660340421 is an apocalyptic number.

It is an amenable number.

660340421 is a deficient number, since it is larger than the sum of its proper divisors (95121979).

660340421 is a wasteful number, since it uses less digits than its factorization.

660340421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24668.

The product of its (nonzero) digits is 3456, while the sum is 26.

The square root of 660340421 is about 25697.0897379450. The cubic root of 660340421 is about 870.8084355745.

Adding to 660340421 its reverse (124043066), we get a palindrome (784383487).

The spelling of 660340421 in words is "six hundred sixty million, three hundred forty thousand, four hundred twenty-one".