55999121 has 2 divisors, whose sum is σ = 55999122. Its totient is φ = 55999120.

The previous prime is 55999079. The next prime is 55999123. The reversal of 55999121 is 12199955.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 49547521 + 6451600 = 7039^2 + 2540^2 .

It is a cyclic number.

It is not a de Polignac number, because 55999121 - 2¹⁴ = 55982737 is a prime.

Together with 55999123, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (55999123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27999560 + 27999561.

It is an arithmetic number, because the mean of its divisors is an integer number (27999561).

Almost surely, 2^55999121 is an apocalyptic number.

It is an amenable number.

55999121 is a deficient number, since it is larger than the sum of its proper divisors (1).

55999121 is an equidigital number, since it uses as much as digits as its factorization.

55999121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 36450, while the sum is 41.

The square root of 55999121 is about 7483.2560426595. The cubic root of 55999121 is about 382.5842347982.

The spelling of 55999121 in words is "fifty-five million, nine hundred ninety-nine thousand, one hundred twenty-one".