1156765821 has 16 divisors (see below), whose sum is σ = 1557316800. Its totient is φ = 763727360.

The previous prime is 1156765807. The next prime is 1156765853. The reversal of 1156765821 is 1285676511.

It is a cyclic number.

It is not a de Polignac number, because 1156765821 - 2⁵ = 1156765789 is a prime.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1156765801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 154126 + ... + 161456.

It is an arithmetic number, because the mean of its divisors is an integer number (97332300).

Almost surely, 2^1156765821 is an apocalyptic number.

It is an amenable number.

1156765821 is a deficient number, since it is larger than the sum of its proper divisors (400550979).

1156765821 is a wasteful number, since it uses less digits than its factorization.

1156765821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7836.

The product of its digits is 100800, while the sum is 42.

The square root of 1156765821 is about 34011.2602089367. The cubic root of 1156765821 is about 1049.7401688145.

The spelling of 1156765821 in words is "one billion, one hundred fifty-six million, seven hundred sixty-five thousand, eight hundred twenty-one".