64638641 has 8 divisors (see below), whose sum is σ = 69733224. Its totient is φ = 59687680.

The previous prime is 64638631. The next prime is 64638647. The reversal of 64638641 is 14683646.

It can be written as a sum of positive squares in 4 ways, for example, as 28398241 + 36240400 = 5329^2 + 6020^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 64638641 - 2¹⁸ = 64376497 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 64638595 and 64638604.

It is not an unprimeable number, because it can be changed into a prime (64638647) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 34970 + ... + 36771.

It is an arithmetic number, because the mean of its divisors is an integer number (8716653).

Almost surely, 2^64638641 is an apocalyptic number.

It is an amenable number.

64638641 is a deficient number, since it is larger than the sum of its proper divisors (5094583).

64638641 is a wasteful number, since it uses less digits than its factorization.

64638641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71811.

The product of its digits is 82944, while the sum is 38.

The square root of 64638641 is about 8039.8159804811. The cubic root of 64638641 is about 401.3261008662.

The spelling of 64638641 in words is "sixty-four million, six hundred thirty-eight thousand, six hundred forty-one".