55242521 has 2 divisors, whose sum is σ = 55242522. Its totient is φ = 55242520.

The previous prime is 55242497. The next prime is 55242529. The reversal of 55242521 is 12524255.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 51768025 + 3474496 = 7195^2 + 1864^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-55242521 is a prime.

It is a super-2 number, since 2×55242521² = 6103472252870882, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (55242529) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27621260 + 27621261.

It is an arithmetic number, because the mean of its divisors is an integer number (27621261).

Almost surely, 2^55242521 is an apocalyptic number.

It is an amenable number.

55242521 is a deficient number, since it is larger than the sum of its proper divisors (1).

55242521 is an equidigital number, since it uses as much as digits as its factorization.

55242521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4000, while the sum is 26.

The square root of 55242521 is about 7432.5312646500. The cubic root of 55242521 is about 380.8533936713.

Adding to 55242521 its reverse (12524255), we get a palindrome (67766776).

The spelling of 55242521 in words is "fifty-five million, two hundred forty-two thousand, five hundred twenty-one".