2188217261 has 2 divisors, whose sum is σ = 2188217262. Its totient is φ = 2188217260.

The previous prime is 2188217257. The next prime is 2188217281. The reversal of 2188217261 is 1627128812.

2188217261 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1163833225 + 1024384036 = 34115^2 + 32006^2 .

It is a cyclic number.

It is not a de Polignac number, because 2188217261 - 2² = 2188217257 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2188217221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1094108630 + 1094108631.

It is an arithmetic number, because the mean of its divisors is an integer number (1094108631).

Almost surely, 2^2188217261 is an apocalyptic number.

It is an amenable number.

2188217261 is a deficient number, since it is larger than the sum of its proper divisors (1).

2188217261 is an equidigital number, since it uses as much as digits as its factorization.

2188217261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21504, while the sum is 38.

The square root of 2188217261 is about 46778.3845488491. The cubic root of 2188217261 is about 1298.2653908542.

The spelling of 2188217261 in words is "two billion, one hundred eighty-eight million, two hundred seventeen thousand, two hundred sixty-one".