1656212126561 has 16 divisors (see below), whose sum is σ = 1752519756288. Its totient is φ = 1562637398400.

The previous prime is 1656212126551. The next prime is 1656212126581.

1656212126561 is nontrivially palindromic in base 10.

It is a cyclic number.

It is not a de Polignac number, because 1656212126561 - 2³⁴ = 1639032257377 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1656212126531) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1445555 + ... + 2324231.

It is an arithmetic number, because the mean of its divisors is an integer number (109532484768).

Almost surely, 2^{1656212126561} is an apocalyptic number.

It is an amenable number.

1656212126561 is a deficient number, since it is larger than the sum of its proper divisors (96307629727).

1656212126561 is a wasteful number, since it uses less digits than its factorization.

1656212126561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 880232.

The product of its digits is 259200, while the sum is 44.

The spelling of 1656212126561 in words is "one trillion, six hundred fifty-six billion, two hundred twelve million, one hundred twenty-six thousand, five hundred sixty-one".