55015021 has 2 divisors, whose sum is σ = 55015022. Its totient is φ = 55015020.

The previous prime is 55015019. The next prime is 55015091. The reversal of 55015021 is 12051055.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 41139396 + 13875625 = 6414^2 + 3725^2 .

It is a cyclic number.

It is not a de Polignac number, because 55015021 - 2¹ = 55015019 is a prime.

Together with 55015019, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 55015021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55015091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27507510 + 27507511.

It is an arithmetic number, because the mean of its divisors is an integer number (27507511).

Almost surely, 2^55015021 is an apocalyptic number.

It is an amenable number.

55015021 is a deficient number, since it is larger than the sum of its proper divisors (1).

55015021 is an equidigital number, since it uses as much as digits as its factorization.

55015021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 250, while the sum is 19.

The square root of 55015021 is about 7417.2111335730. The cubic root of 55015021 is about 380.3298636212.

Adding to 55015021 its reverse (12051055), we get a palindrome (67066076).

The spelling of 55015021 in words is "fifty-five million, fifteen thousand, twenty-one".