63509921 has 2 divisors, whose sum is σ = 63509922. Its totient is φ = 63509920.

The previous prime is 63509881. The next prime is 63509947. The reversal of 63509921 is 12990536.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 48455521 + 15054400 = 6961^2 + 3880^2 .

It is a cyclic number.

It is not a de Polignac number, because 63509921 - 2¹⁸ = 63247777 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (63509981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 31754960 + 31754961.

It is an arithmetic number, because the mean of its divisors is an integer number (31754961).

Almost surely, 2^63509921 is an apocalyptic number.

It is an amenable number.

63509921 is a deficient number, since it is larger than the sum of its proper divisors (1).

63509921 is an equidigital number, since it uses as much as digits as its factorization.

63509921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 14580, while the sum is 35.

The square root of 63509921 is about 7969.3111998466. The cubic root of 63509921 is about 398.9763848478.

The spelling of 63509921 in words is "sixty-three million, five hundred nine thousand, nine hundred twenty-one".