2188695581 has 2 divisors, whose sum is σ = 2188695582. Its totient is φ = 2188695580.

The previous prime is 2188695541. The next prime is 2188695589. The reversal of 2188695581 is 1855968812.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1771147225 + 417548356 = 42085^2 + 20434^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2188695581 is a prime.

It is a super-2 number, since 2×2188695581² = 9580776692577855122, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2188695589) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1094347790 + 1094347791.

It is an arithmetic number, because the mean of its divisors is an integer number (1094347791).

Almost surely, 2^2188695581 is an apocalyptic number.

It is an amenable number.

2188695581 is a deficient number, since it is larger than the sum of its proper divisors (1).

2188695581 is an equidigital number, since it uses as much as digits as its factorization.

2188695581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1382400, while the sum is 53.

The square root of 2188695581 is about 46783.4968872572. The cubic root of 2188695581 is about 1298.3599794296.

The spelling of 2188695581 in words is "two billion, one hundred eighty-eight million, six hundred ninety-five thousand, five hundred eighty-one".