840248557 has 2 divisors, whose sum is σ = 840248558. Its totient is φ = 840248556.

The previous prime is 840248543. The next prime is 840248567. The reversal of 840248557 is 755842048.

It is a happy number.

840248557 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 502387396 + 337861161 = 22414^2 + 18381^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-840248557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (840248567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 420124278 + 420124279.

It is an arithmetic number, because the mean of its divisors is an integer number (420124279).

Almost surely, 2^840248557 is an apocalyptic number.

It is an amenable number.

840248557 is a deficient number, since it is larger than the sum of its proper divisors (1).

840248557 is an equidigital number, since it uses as much as digits as its factorization.

840248557 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 358400, while the sum is 43.

The square root of 840248557 is about 28987.0411908494. The cubic root of 840248557 is about 943.6318516365.

The spelling of 840248557 in words is "eight hundred forty million, two hundred forty-eight thousand, five hundred fifty-seven".