660441421 has 2 divisors, whose sum is σ = 660441422. Its totient is φ = 660441420.

The previous prime is 660441409. The next prime is 660441433. The reversal of 660441421 is 124144066.

It is a balanced prime because it is at equal distance from previous prime (660441409) and next prime (660441433).

It can be written as a sum of positive squares in only one way, i.e., 556299396 + 104142025 = 23586^2 + 10205^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-660441421 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 660441421.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (660441401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330220710 + 330220711.

It is an arithmetic number, because the mean of its divisors is an integer number (330220711).

Almost surely, 2^660441421 is an apocalyptic number.

It is an amenable number.

660441421 is a deficient number, since it is larger than the sum of its proper divisors (1).

660441421 is an equidigital number, since it uses as much as digits as its factorization.

660441421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4608, while the sum is 28.

The square root of 660441421 is about 25699.0548658895. The cubic root of 660441421 is about 870.8528304378.

Adding to 660441421 its reverse (124144066), we get a palindrome (784585487).

The spelling of 660441421 in words is "six hundred sixty million, four hundred forty-one thousand, four hundred twenty-one".