2161640313225 has 36 divisors (see below), whose sum is σ = 3880100455296. Its totient is φ = 1150384767840.

The previous prime is 2161640313199. The next prime is 2161640313227. The reversal of 2161640313225 is 5223130461612.

2161640313225 is a `hidden beast` number, since 2 + 1 + 6 + 1 + 640 + 3 + 1 + 3 + 2 + 2 + 5 = 666.

It is not a de Polignac number, because 2161640313225 - 2⁸ = 2161640312969 is a prime.

It is a super-2 number, since 2×2161640313225² (a number of 25 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 2161640313225.

It is not an unprimeable number, because it can be changed into a prime (2161640313227) 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 35 ways as a sum of consecutive naturals, for example, 10270869 + ... + 10479218.

Almost surely, 2^{2161640313225} is an apocalyptic number.

2161640313225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

2161640313225 is a deficient number, since it is larger than the sum of its proper divisors (1718460142071).

2161640313225 is a wasteful number, since it uses less digits than its factorization.

2161640313225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20750566 (or 20750558 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

Adding to 2161640313225 its reverse (5223130461612), we get a palindrome (7384770774837).

The spelling of 2161640313225 in words is "two trillion, one hundred sixty-one billion, six hundred forty million, three hundred thirteen thousand, two hundred twenty-five".