1656005505561 has 32 divisors (see below), whose sum is σ = 2716318425600. Its totient is φ = 988659991440.

The previous prime is 1656005505467. The next prime is 1656005505569. The reversal of 1656005505561 is 1655055006561.

It is not a de Polignac number, because 1656005505561 - 2⁷ = 1656005505433 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1656005505569) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 41590371 + ... + 41630168.

It is an arithmetic number, because the mean of its divisors is an integer number (84884950800).

Almost surely, 2^{1656005505561} is an apocalyptic number.

1656005505561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1656005505561 is a deficient number, since it is larger than the sum of its proper divisors (1060312920039).

1656005505561 is a wasteful number, since it uses less digits than its factorization.

1656005505561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83220626 (or 83220620 counting only the distinct ones).

The product of its (nonzero) digits is 675000, while the sum is 45.

The spelling of 1656005505561 in words is "one trillion, six hundred fifty-six billion, five million, five hundred five thousand, five hundred sixty-one".