63539921 has 2 divisors, whose sum is σ = 63539922. Its totient is φ = 63539920.

The previous prime is 63539887. The next prime is 63539923. The reversal of 63539921 is 12993536.

63539921 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., 59459521 + 4080400 = 7711^2 + 2020^2 .

It is a cyclic number.

It is not a de Polignac number, because 63539921 - 2¹⁰ = 63538897 is a prime.

Together with 63539923, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (63539923) 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, 31769960 + 31769961.

It is an arithmetic number, because the mean of its divisors is an integer number (31769961).

Almost surely, 2^63539921 is an apocalyptic number.

It is an amenable number.

63539921 is a deficient number, since it is larger than the sum of its proper divisors (1).

63539921 is an equidigital number, since it uses as much as digits as its factorization.

63539921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 43740, while the sum is 38.

The square root of 63539921 is about 7971.1931980099. The cubic root of 63539921 is about 399.0391960707.

The spelling of 63539921 in words is "sixty-three million, five hundred thirty-nine thousand, nine hundred twenty-one".