2161621243325 has 12 divisors (see below), whose sum is σ = 2724351496788. Its totient is φ = 1700947862400.

The previous prime is 2161621243321. The next prime is 2161621243333. The reversal of 2161621243325 is 5233421261612.

It can be written as a sum of positive squares in 6 ways, for example, as 523889335204 + 1637731908121 = 723802^2 + 1279739^2 .

It is not a de Polignac number, because 2161621243325 - 2² = 2161621243321 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2161621243321) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 708726752 + ... + 708729801.

It is an arithmetic number, because the mean of its divisors is an integer number (227029291399).

Almost surely, 2^{2161621243325} is an apocalyptic number.

2161621243325 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

2161621243325 is a deficient number, since it is larger than the sum of its proper divisors (562730253463).

2161621243325 is a wasteful number, since it uses less digits than its factorization.

2161621243325 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1417456624 (or 1417456619 counting only the distinct ones).

The product of its digits is 103680, while the sum is 38.

The spelling of 2161621243325 in words is "two trillion, one hundred sixty-one billion, six hundred twenty-one million, two hundred forty-three thousand, three hundred twenty-five".