2166221561465 has 16 divisors (see below), whose sum is σ = 2799691549200. Its totient is φ = 1599518871552.

The previous prime is 2166221561437. The next prime is 2166221561477. The reversal of 2166221561465 is 5641651226612.

It can be written as a sum of positive squares in 8 ways, for example, as 340336891456 + 1825884670009 = 583384^2 + 1351253^2 .

It is a cyclic number.

It is not a de Polignac number, because 2166221561465 - 2⁶ = 2166221561401 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 898220 + ... + 2266989.

It is an arithmetic number, because the mean of its divisors is an integer number (174980721825).

Almost surely, 2^{2166221561465} is an apocalyptic number.

It is an amenable number.

2166221561465 is a deficient number, since it is larger than the sum of its proper divisors (633469987735).

2166221561465 is a wasteful number, since it uses less digits than its factorization.

2166221561465 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3175756.

The product of its digits is 1036800, while the sum is 47.

The spelling of 2166221561465 in words is "two trillion, one hundred sixty-six billion, two hundred twenty-one million, five hundred sixty-one thousand, four hundred sixty-five".