1643613615656 has 8 divisors (see below), whose sum is σ = 3081775529370. Its totient is φ = 821806807824.

The previous prime is 1643613615601. The next prime is 1643613615659. The reversal of 1643613615656 is 6565163163461.

It can be written as a sum of positive squares in only one way, i.e., 1278785535556 + 364828080100 = 1130834^2 + 604010^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a junction number, because it is equal to n+sod(n) for n = 1643613615598 and 1643613615607.

It is not an unprimeable number, because it can be changed into a prime (1643613615659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102725850971 + ... + 102725850986.

Almost surely, 2^{1643613615656} is an apocalyptic number.

It is an amenable number.

1643613615656 is a deficient number, since it is larger than the sum of its proper divisors (1438161913714).

1643613615656 is a wasteful number, since it uses less digits than its factorization.

1643613615656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 205451701963 (or 205451701959 counting only the distinct ones).

The product of its digits is 6998400, while the sum is 53.

The spelling of 1643613615656 in words is "one trillion, six hundred forty-three billion, six hundred thirteen million, six hundred fifteen thousand, six hundred fifty-six".