660706421 has 2 divisors, whose sum is σ = 660706422. Its totient is φ = 660706420.

The previous prime is 660706393. The next prime is 660706493. The reversal of 660706421 is 124607066.

660706421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 478078225 + 182628196 = 21865^2 + 13514^2 .

It is a cyclic number.

It is not a de Polignac number, because 660706421 - 2²² = 656512117 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (660700421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330353210 + 330353211.

It is an arithmetic number, because the mean of its divisors is an integer number (330353211).

Almost surely, 2^660706421 is an apocalyptic number.

It is an amenable number.

660706421 is a deficient number, since it is larger than the sum of its proper divisors (1).

660706421 is an equidigital number, since it uses as much as digits as its factorization.

660706421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12096, while the sum is 32.

The square root of 660706421 is about 25704.2101804354. The cubic root of 660706421 is about 870.9692904970.

The spelling of 660706421 in words is "six hundred sixty million, seven hundred six thousand, four hundred twenty-one".