63868561 has 4 divisors (see below), whose sum is σ = 63915300. Its totient is φ = 63821824.

The previous prime is 63868559. The next prime is 63868579. The reversal of 63868561 is 16586836.

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 14250625 + 49617936 = 3775^2 + 7044^2 .

It is a cyclic number.

It is not a de Polignac number, because 63868561 - 2¹ = 63868559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (63868501) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21256 + ... + 24073.

It is an arithmetic number, because the mean of its divisors is an integer number (15978825).

Almost surely, 2^63868561 is an apocalyptic number.

It is an amenable number.

63868561 is a deficient number, since it is larger than the sum of its proper divisors (46739).

63868561 is a wasteful number, since it uses less digits than its factorization.

63868561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46738.

The product of its digits is 207360, while the sum is 43.

The square root of 63868561 is about 7991.7808403384. The cubic root of 63868561 is about 399.7259810769.

It can be divided in two parts, 63 and 868561, that added together give a square (868624 = 932²).

The spelling of 63868561 in words is "sixty-three million, eight hundred sixty-eight thousand, five hundred sixty-one".