5550561661 has 2 divisors, whose sum is σ = 5550561662. Its totient is φ = 5550561660.

The previous prime is 5550561631. The next prime is 5550561677. The reversal of 5550561661 is 1661650555.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5070294436 + 480267225 = 71206^2 + 21915^2 .

It is a cyclic number.

It is not a de Polignac number, because 5550561661 - 2¹¹ = 5550559613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (5550561631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2775280830 + 2775280831.

It is an arithmetic number, because the mean of its divisors is an integer number (2775280831).

Almost surely, 2^5550561661 is an apocalyptic number.

It is an amenable number.

5550561661 is a deficient number, since it is larger than the sum of its proper divisors (1).

5550561661 is an equidigital number, since it uses as much as digits as its factorization.

5550561661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 135000, while the sum is 40.

The square root of 5550561661 is about 74502.0916552012. The cubic root of 5550561661 is about 1770.5667757308.

The spelling of 5550561661 in words is "five billion, five hundred fifty million, five hundred sixty-one thousand, six hundred sixty-one".