39906421 has 2 divisors, whose sum is σ = 39906422. Its totient is φ = 39906420.

The previous prime is 39906389. The next prime is 39906437. The reversal of 39906421 is 12460993.

39906421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 29311396 + 10595025 = 5414^2 + 3255^2 .

It is a cyclic number.

It is not a de Polignac number, because 39906421 - 2⁵ = 39906389 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (39906121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19953210 + 19953211.

It is an arithmetic number, because the mean of its divisors is an integer number (19953211).

Almost surely, 2^39906421 is an apocalyptic number.

It is an amenable number.

39906421 is a deficient number, since it is larger than the sum of its proper divisors (1).

39906421 is an equidigital number, since it uses as much as digits as its factorization.

39906421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11664, while the sum is 34.

The square root of 39906421 is about 6317.1529188393. The cubic root of 39906421 is about 341.7282846896.

The spelling of 39906421 in words is "thirty-nine million, nine hundred six thousand, four hundred twenty-one".