63840521 has 4 divisors (see below), whose sum is σ = 63870612. Its totient is φ = 63810432.

The previous prime is 63840499. The next prime is 63840527. The reversal of 63840521 is 12504836.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 12503296 + 51337225 = 3536^2 + 7165^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-63840521 is a prime.

It is a super-2 number, since 2×63840521² = 8151224243102882, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (63840527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11600 + ... + 16193.

It is an arithmetic number, because the mean of its divisors is an integer number (15967653).

Almost surely, 2^63840521 is an apocalyptic number.

It is an amenable number.

63840521 is a deficient number, since it is larger than the sum of its proper divisors (30091).

63840521 is a wasteful number, since it uses less digits than its factorization.

63840521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30090.

The product of its (nonzero) digits is 5760, while the sum is 29.

The square root of 63840521 is about 7990.0263453884. The cubic root of 63840521 is about 399.6674757290.

The spelling of 63840521 in words is "sixty-three million, eight hundred forty thousand, five hundred twenty-one".