1156820691861 has 6 divisors (see below), whose sum is σ = 1670963221590. Its totient is φ = 771213794568.

The previous prime is 1156820691833. The next prime is 1156820691869. The reversal of 1156820691861 is 1681960286511.

1156820691861 is a `hidden beast` number, since 1 + 1 + 568 + 2 + 0 + 6 + 9 + 18 + 61 = 666.

It can be written as a sum of positive squares in only one way, i.e., 797504366961 + 359316324900 = 893031^2 + 599430^2 .

It is not a de Polignac number, because 1156820691861 - 2⁶ = 1156820691797 is a prime.

It is a super-2 number, since 2×1156820691861² (a number of 25 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1156820691798 and 1156820691807.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1156820691869) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 64267816206 + ... + 64267816223.

It is an arithmetic number, because the mean of its divisors is an integer number (278493870265).

Almost surely, 2^{1156820691861} is an apocalyptic number.

It is an amenable number.

1156820691861 is a deficient number, since it is larger than the sum of its proper divisors (514142529729).

1156820691861 is a wasteful number, since it uses less digits than its factorization.

1156820691861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128535632435 (or 128535632432 counting only the distinct ones).

The product of its (nonzero) digits is 1244160, while the sum is 54.

The spelling of 1156820691861 in words is "one trillion, one hundred fifty-six billion, eight hundred twenty million, six hundred ninety-one thousand, eight hundred sixty-one".