55121389 has 2 divisors, whose sum is σ = 55121390. Its totient is φ = 55121388.

The previous prime is 55121359. The next prime is 55121393. The reversal of 55121389 is 98312155.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 42575625 + 12545764 = 6525^2 + 3542^2 .

It is a cyclic number.

It is not a de Polignac number, because 55121389 - 2¹³ = 55113197 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55121359) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27560694 + 27560695.

It is an arithmetic number, because the mean of its divisors is an integer number (27560695).

Almost surely, 2^55121389 is an apocalyptic number.

It is an amenable number.

55121389 is a deficient number, since it is larger than the sum of its proper divisors (1).

55121389 is an equidigital number, since it uses as much as digits as its factorization.

55121389 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10800, while the sum is 34.

The square root of 55121389 is about 7424.3780210870. The cubic root of 55121389 is about 380.5748202520.

The spelling of 55121389 in words is "fifty-five million, one hundred twenty-one thousand, three hundred eighty-nine".