2165221125 has 56 divisors (see below), whose sum is σ = 4051611096. Its totient is φ = 1154736000.

The previous prime is 2165221073. The next prime is 2165221141. The reversal of 2165221125 is 5211225612.

2165221125 is a `hidden beast` number, since 2 + 1 + 652 + 2 + 1 + 1 + 2 + 5 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 73256481 + 2091964644 = 8559^2 + 45738^2 .

It is not a de Polignac number, because 2165221125 - 2⁶ = 2165221061 is a prime.

It is a super-3 number, since 3×2165221125³ (a number of 29 digits) contains 333 as substring.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 79245 + ... + 103005.

Almost surely, 2^2165221125 is an apocalyptic number.

2165221125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

2165221125 is a deficient number, since it is larger than the sum of its proper divisors (1886389971).

2165221125 is an frugal number, since it uses more digits than its factorization.

2165221125 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23794 (or 23769 counting only the distinct ones).

The product of its digits is 2400, while the sum is 27.

The square root of 2165221125 is about 46531.9366134701. The cubic root of 2165221125 is about 1293.7015104700.

Adding to 2165221125 its reverse (5211225612), we get a palindrome (7376446737).

The spelling of 2165221125 in words is "two billion, one hundred sixty-five million, two hundred twenty-one thousand, one hundred twenty-five".