1644663605455 has 64 divisors (see below), whose sum is σ = 2196516833280. Its totient is φ = 1174322935296.

The previous prime is 1644663605419. The next prime is 1644663605461. The reversal of 1644663605455 is 5545063664461.

It is a cyclic number.

It is not a de Polignac number, because 1644663605455 - 2¹⁷ = 1644663474383 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1644663605396 and 1644663605405.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 277671124 + ... + 277677046.

It is an arithmetic number, because the mean of its divisors is an integer number (34320575520).

Almost surely, 2^{1644663605455} is an apocalyptic number.

1644663605455 is a deficient number, since it is larger than the sum of its proper divisors (551853227825).

1644663605455 is a wasteful number, since it uses less digits than its factorization.

1644663605455 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6680.

The product of its (nonzero) digits is 31104000, while the sum is 55.

The spelling of 1644663605455 in words is "one trillion, six hundred forty-four billion, six hundred sixty-three million, six hundred five thousand, four hundred fifty-five".