1056665215661 has 16 divisors (see below), whose sum is σ = 1228754918400. Its totient is φ = 898527006000.

The previous prime is 1056665215651. The next prime is 1056665215687. The reversal of 1056665215661 is 1665125666501.

It is a happy number.

1056665215661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 1056665215661 - 2¹⁴ = 1056665199277 is a prime.

It is a super-2 number, since 2×1056665215661² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1056665215651) 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, 31982315 + ... + 32015336.

It is an arithmetic number, because the mean of its divisors is an integer number (76797182400).

Almost surely, 2^{1056665215661} is an apocalyptic number.

1056665215661 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1056665215661 is a deficient number, since it is larger than the sum of its proper divisors (172089702739).

1056665215661 is a wasteful number, since it uses less digits than its factorization.

1056665215661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63997760.

The product of its (nonzero) digits is 1944000, while the sum is 50.

The spelling of 1056665215661 in words is "one trillion, fifty-six billion, six hundred sixty-five million, two hundred fifteen thousand, six hundred sixty-one".