55203721 has 4 divisors (see below), whose sum is σ = 58109200. Its totient is φ = 52298244.

The previous prime is 55203697. The next prime is 55203727. The reversal of 55203721 is 12730255.

55203721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12730255 = 5 ⋅2546051.

It is a cyclic number.

It is not a de Polignac number, because 55203721 - 2¹⁹ = 54679433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (55203727) 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 in 3 ways as a sum of consecutive naturals, for example, 1452711 + ... + 1452748.

It is an arithmetic number, because the mean of its divisors is an integer number (14527300).

Almost surely, 2^55203721 is an apocalyptic number.

It is an amenable number.

55203721 is a deficient number, since it is larger than the sum of its proper divisors (2905479).

55203721 is a wasteful number, since it uses less digits than its factorization.

55203721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2905478.

The product of its (nonzero) digits is 2100, while the sum is 25.

The square root of 55203721 is about 7429.9206590649. The cubic root of 55203721 is about 380.7642077064.

Adding to 55203721 its reverse (12730255), we get a palindrome (67933976).

The spelling of 55203721 in words is "fifty-five million, two hundred three thousand, seven hundred twenty-one".