3644640221647 has 2 divisors, whose sum is σ = 3644640221648. Its totient is φ = 3644640221646.

The previous prime is 3644640221513. The next prime is 3644640221681. The reversal of 3644640221647 is 7461220464463.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3644640221647 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 3644640221647.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3644640227647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1822320110823 + 1822320110824.

It is an arithmetic number, because the mean of its divisors is an integer number (1822320110824).

Almost surely, 2^{3644640221647} is an apocalyptic number.

3644640221647 is a deficient number, since it is larger than the sum of its proper divisors (1).

3644640221647 is an equidigital number, since it uses as much as digits as its factorization.

3644640221647 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4644864, while the sum is 49.

The spelling of 3644640221647 in words is "three trillion, six hundred forty-four billion, six hundred forty million, two hundred twenty-one thousand, six hundred forty-seven".