5555216621 has 2 divisors, whose sum is σ = 5555216622. Its totient is φ = 5555216620.

The previous prime is 5555216609. The next prime is 5555216629. The reversal of 5555216621 is 1266125555.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5553975625 + 1240996 = 74525^2 + 1114^2 .

It is a cyclic number.

It is not a de Polignac number, because 5555216621 - 2¹⁰ = 5555215597 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (5555216629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2777608310 + 2777608311.

It is an arithmetic number, because the mean of its divisors is an integer number (2777608311).

Almost surely, 2^5555216621 is an apocalyptic number.

It is an amenable number.

5555216621 is a deficient number, since it is larger than the sum of its proper divisors (1).

5555216621 is an equidigital number, since it uses as much as digits as its factorization.

5555216621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 90000, while the sum is 38.

The square root of 5555216621 is about 74533.3255731958. The cubic root of 5555216621 is about 1771.0615974009.

The spelling of 5555216621 in words is "five billion, five hundred fifty-five million, two hundred sixteen thousand, six hundred twenty-one".