55420213561 has 2 divisors, whose sum is σ = 55420213562. Its totient is φ = 55420213560.

The previous prime is 55420213529. The next prime is 55420213573. The reversal of 55420213561 is 16531202455.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 33367963561 + 22052250000 = 182669^2 + 148500^2 .

It is a cyclic number.

It is not a de Polignac number, because 55420213561 - 2⁵ = 55420213529 is a prime.

It is a super-2 number, since 2×55420213561² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (55420213501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27710106780 + 27710106781.

It is an arithmetic number, because the mean of its divisors is an integer number (27710106781).

Almost surely, 2^55420213561 is an apocalyptic number.

It is an amenable number.

55420213561 is a deficient number, since it is larger than the sum of its proper divisors (1).

55420213561 is an equidigital number, since it uses as much as digits as its factorization.

55420213561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36000, while the sum is 34.

The spelling of 55420213561 in words is "fifty-five billion, four hundred twenty million, two hundred thirteen thousand, five hundred sixty-one".