85155243821 has 4 divisors (see below), whose sum is σ = 85936484700. Its totient is φ = 84374002944.

The previous prime is 85155243787. The next prime is 85155243827. The reversal of 85155243821 is 12834255158.

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 68743071721 + 16412172100 = 262189^2 + 128110^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-85155243821 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 (85155243827) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 390620276 + ... + 390620493.

It is an arithmetic number, because the mean of its divisors is an integer number (21484121175).

Almost surely, 2^85155243821 is an apocalyptic number.

It is an amenable number.

85155243821 is a deficient number, since it is larger than the sum of its proper divisors (781240879).

85155243821 is a wasteful number, since it uses less digits than its factorization.

85155243821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 781240878.

The product of its digits is 384000, while the sum is 44.

Adding to 85155243821 its reverse (12834255158), we get a palindrome (97989498979).

The spelling of 85155243821 in words is "eighty-five billion, one hundred fifty-five million, two hundred forty-three thousand, eight hundred twenty-one".