39972421 has 2 divisors, whose sum is σ = 39972422. Its totient is φ = 39972420.

The previous prime is 39972407. The next prime is 39972431. The reversal of 39972421 is 12427993.

39972421 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., 39564100 + 408321 = 6290^2 + 639^2 .

It is a cyclic number.

It is not a de Polignac number, because 39972421 - 2⁷ = 39972293 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (39972431) 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, 19986210 + 19986211.

It is an arithmetic number, because the mean of its divisors is an integer number (19986211).

Almost surely, 2^39972421 is an apocalyptic number.

It is an amenable number.

39972421 is a deficient number, since it is larger than the sum of its proper divisors (1).

39972421 is an equidigital number, since it uses as much as digits as its factorization.

39972421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27216, while the sum is 37.

The square root of 39972421 is about 6322.3746329999. The cubic root of 39972421 is about 341.9165722200.

The spelling of 39972421 in words is "thirty-nine million, nine hundred seventy-two thousand, four hundred twenty-one".