64644440646403 has 4 divisors (see below), whose sum is σ = 65072549525008. Its totient is φ = 64216331767800.

The previous prime is 64644440646377. The next prime is 64644440646413. The reversal of 64644440646403 is 30464604444646.

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

It is a cyclic number.

It is not a de Polignac number, because 64644440646403 - 2⁴⁵ = 29460068557571 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64644440646413) 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, 214054439076 + ... + 214054439377.

It is an arithmetic number, because the mean of its divisors is an integer number (16268137381252).

Almost surely, 2^{64644440646403} is an apocalyptic number.

64644440646403 is a deficient number, since it is larger than the sum of its proper divisors (428108878605).

64644440646403 is a wasteful number, since it uses less digits than its factorization.

64644440646403 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 428108878604.

The product of its (nonzero) digits is 63700992, while the sum is 55.

The spelling of 64644440646403 in words is "sixty-four trillion, six hundred forty-four billion, four hundred forty million, six hundred forty-six thousand, four hundred three".