55517921 has 2 divisors, whose sum is σ = 55517922. Its totient is φ = 55517920.

The previous prime is 55517909. The next prime is 55517939. The reversal of 55517921 is 12971555.

55517921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 45373696 + 10144225 = 6736^2 + 3185^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-55517921 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (55517941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27758960 + 27758961.

It is an arithmetic number, because the mean of its divisors is an integer number (27758961).

Almost surely, 2^55517921 is an apocalyptic number.

It is an amenable number.

55517921 is a deficient number, since it is larger than the sum of its proper divisors (1).

55517921 is an equidigital number, since it uses as much as digits as its factorization.

55517921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15750, while the sum is 35.

The square root of 55517921 is about 7451.0348945633. The cubic root of 55517921 is about 381.4852330977.

The spelling of 55517921 in words is "fifty-five million, five hundred seventeen thousand, nine hundred twenty-one".