2165540651 has 4 divisors (see below), whose sum is σ = 2211616032. Its totient is φ = 2119465272.

The previous prime is 2165540639. The next prime is 2165540659. The reversal of 2165540651 is 1560455612.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 2165540651 - 2²² = 2161346347 is a prime.

It is a super-2 number, since 2×2165540651² = 9379132622267007602, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2165540659) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23037620 + ... + 23037713.

It is an arithmetic number, because the mean of its divisors is an integer number (552904008).

Almost surely, 2^2165540651 is an apocalyptic number.

2165540651 is a deficient number, since it is larger than the sum of its proper divisors (46075381).

2165540651 is an equidigital number, since it uses as much as digits as its factorization.

2165540651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46075380.

The product of its (nonzero) digits is 36000, while the sum is 35.

The square root of 2165540651 is about 46535.3698921584. The cubic root of 2165540651 is about 1293.7651453772.

The spelling of 2165540651 in words is "two billion, one hundred sixty-five million, five hundred forty thousand, six hundred fifty-one".