2188638461 has 2 divisors, whose sum is σ = 2188638462. Its totient is φ = 2188638460.

The previous prime is 2188638457. The next prime is 2188638479. The reversal of 2188638461 is 1648368812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1522482361 + 666156100 = 39019^2 + 25810^2 .

It is a cyclic number.

It is not a de Polignac number, because 2188638461 - 2² = 2188638457 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2188638421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1094319230 + 1094319231.

It is an arithmetic number, because the mean of its divisors is an integer number (1094319231).

Almost surely, 2^2188638461 is an apocalyptic number.

It is an amenable number.

2188638461 is a deficient number, since it is larger than the sum of its proper divisors (1).

2188638461 is an equidigital number, since it uses as much as digits as its factorization.

2188638461 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 442368, while the sum is 47.

The square root of 2188638461 is about 46782.8864115929. The cubic root of 2188638461 is about 1298.3486845792.

The spelling of 2188638461 in words is "two billion, one hundred eighty-eight million, six hundred thirty-eight thousand, four hundred sixty-one".