55242421 has 4 divisors (see below), whose sum is σ = 59491852. Its totient is φ = 50992992.

The previous prime is 55242391. The next prime is 55242479. The reversal of 55242421 is 12424255.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 27300625 + 27941796 = 5225^2 + 5286^2 .

It is a cyclic number.

It is not a de Polignac number, because 55242421 - 2⁹ = 55241909 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55242521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2124696 + ... + 2124721.

It is an arithmetic number, because the mean of its divisors is an integer number (14872963).

Almost surely, 2^55242421 is an apocalyptic number.

It is an amenable number.

55242421 is a deficient number, since it is larger than the sum of its proper divisors (4249431).

55242421 is a wasteful number, since it uses less digits than its factorization.

55242421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4249430.

The product of its digits is 3200, while the sum is 25.

The square root of 55242421 is about 7432.5245374637. The cubic root of 55242421 is about 380.8531638643.

Adding to 55242421 its reverse (12424255), we get a palindrome (67666676).

The spelling of 55242421 in words is "fifty-five million, two hundred forty-two thousand, four hundred twenty-one".