866511511237801 has 32 divisors (see below), whose sum is σ = 1044369166974336. Its totient is φ = 708359471040000.

The previous prime is 866511511237789. The next prime is 866511511237819. The reversal of 866511511237801 is 108732115115668.

It is not a de Polignac number, because 866511511237801 - 2³⁹ = 865961755423913 is a prime.

It is a super-2 number, since 2×866511511237801² (a number of 31 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (866511511237891) 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 31 ways as a sum of consecutive naturals, for example, 105183775 + ... + 113122276.

It is an arithmetic number, because the mean of its divisors is an integer number (32636536467948).

Almost surely, 2^{866511511237801} is an apocalyptic number.

It is an amenable number.

866511511237801 is a deficient number, since it is larger than the sum of its proper divisors (177857655736535).

866511511237801 is a wasteful number, since it uses less digits than its factorization.

866511511237801 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 218306793.

The product of its (nonzero) digits is 2419200, while the sum is 55.

The spelling of 866511511237801 in words is "eight hundred sixty-six trillion, five hundred eleven billion, five hundred eleven million, two hundred thirty-seven thousand, eight hundred one".