840252521389 has 4 divisors (see below), whose sum is σ = 840341568924. Its totient is φ = 840163473856.

The previous prime is 840252521363. The next prime is 840252521411. The reversal of 840252521389 is 983125252048.

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 737266084164 + 102986437225 = 858642^2 + 320915^2 .

It is a 3-Lehmer number, since φ(840252521389) divides (840252521389-1)³.

It is a cyclic number.

It is not a de Polignac number, because 840252521389 - 2⁷ = 840252521261 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 (840252521989) by changing a digit.

It is a nontrivial repunit in base 9436.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 44509612 + ... + 44528485.

It is an arithmetic number, because the mean of its divisors is an integer number (210085392231).

Almost surely, 2^840252521389 is an apocalyptic number.

It is an amenable number.

840252521389 is a deficient number, since it is larger than the sum of its proper divisors (89047535).

840252521389 is an equidigital number, since it uses as much as digits as its factorization.

840252521389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89047534.

The product of its (nonzero) digits is 1382400, while the sum is 49.

The spelling of 840252521389 in words is "eight hundred forty billion, two hundred fifty-two million, five hundred twenty-one thousand, three hundred eighty-nine".