248540021 has 2 divisors, whose sum is σ = 248540022. Its totient is φ = 248540020.

The previous prime is 248540011. The next prime is 248540023. The reversal of 248540021 is 120045842.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 215062225 + 33477796 = 14665^2 + 5786^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-248540021 is a prime.

Together with 248540023, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (248540023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 124270010 + 124270011.

It is an arithmetic number, because the mean of its divisors is an integer number (124270011).

Almost surely, 2^248540021 is an apocalyptic number.

It is an amenable number.

248540021 is a deficient number, since it is larger than the sum of its proper divisors (1).

248540021 is an equidigital number, since it uses as much as digits as its factorization.

248540021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2560, while the sum is 26.

The square root of 248540021 is about 15765.1521083686. The cubic root of 248540021 is about 628.7318244821.

Adding to 248540021 its reverse (120045842), we get a palindrome (368585863).

The spelling of 248540021 in words is "two hundred forty-eight million, five hundred forty thousand, twenty-one".