2121616397 has 4 divisors (see below), whose sum is σ = 2121728796. Its totient is φ = 2121504000.

The previous prime is 2121616339. The next prime is 2121616421. The reversal of 2121616397 is 7936161212.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 569729161 + 1551887236 = 23869^2 + 39394^2 .

It is a cyclic number.

It is not a de Polignac number, because 2121616397 - 2¹⁶ = 2121550861 is a prime.

It is a super-2 number, since 2×2121616397² = 9002512272038523218, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2121616397.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121616897) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20198 + ... + 68199.

It is an arithmetic number, because the mean of its divisors is an integer number (530432199).

Almost surely, 2^2121616397 is an apocalyptic number.

It is an amenable number.

2121616397 is a deficient number, since it is larger than the sum of its proper divisors (112399).

2121616397 is an equidigital number, since it uses as much as digits as its factorization.

2121616397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 112398.

The product of its digits is 27216, while the sum is 38.

The square root of 2121616397 is about 46061.0073380946. The cubic root of 2121616397 is about 1284.9580645118.

The spelling of 2121616397 in words is "two billion, one hundred twenty-one million, six hundred sixteen thousand, three hundred ninety-seven".