55078021 has 2 divisors, whose sum is σ = 55078022. Its totient is φ = 55078020.

The previous prime is 55078013. The next prime is 55078039. The reversal of 55078021 is 12087055.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 51696100 + 3381921 = 7190^2 + 1839^2 .

It is a cyclic number.

It is not a de Polignac number, because 55078021 - 2³ = 55078013 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55078061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27539010 + 27539011.

It is an arithmetic number, because the mean of its divisors is an integer number (27539011).

Almost surely, 2^55078021 is an apocalyptic number.

It is an amenable number.

55078021 is a deficient number, since it is larger than the sum of its proper divisors (1).

55078021 is an equidigital number, since it uses as much as digits as its factorization.

55078021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2800, while the sum is 28.

The square root of 55078021 is about 7421.4567976914. The cubic root of 55078021 is about 380.4749854481.

The spelling of 55078021 in words is "fifty-five million, seventy-eight thousand, twenty-one".