2113121261 has 2 divisors, whose sum is σ = 2113121262. Its totient is φ = 2113121260.

The previous prime is 2113121249. The next prime is 2113121281. The reversal of 2113121261 is 1621213112.

It is an a-pointer prime, because the next prime (2113121281) can be obtained adding 2113121261 to its sum of digits (20).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1972248100 + 140873161 = 44410^2 + 11869^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2113121261 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2113121201) 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 as a sum of consecutive naturals, namely, 1056560630 + 1056560631.

It is an arithmetic number, because the mean of its divisors is an integer number (1056560631).

Almost surely, 2^2113121261 is an apocalyptic number.

It is an amenable number.

2113121261 is a deficient number, since it is larger than the sum of its proper divisors (1).

2113121261 is an equidigital number, since it uses as much as digits as its factorization.

2113121261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 144, while the sum is 20.

The square root of 2113121261 is about 45968.6987090129. The cubic root of 2113121261 is about 1283.2407425337.

Adding to 2113121261 its reverse (1621213112), we get a palindrome (3734334373).

The spelling of 2113121261 in words is "two billion, one hundred thirteen million, one hundred twenty-one thousand, two hundred sixty-one".