77889833217 has 54 divisors (see below), whose sum is σ = 131544037638. Its totient is φ = 44281810944.

The previous prime is 77889833191. The next prime is 77889833237. The reversal of 77889833217 is 71233898877.

It can be written as a sum of positive squares in 3 ways, for example, as 40001600016 + 37888233201 = 200004^2 + 194649^2 .

It is not a de Polignac number, because 77889833217 - 2⁷ = 77889833089 is a prime.

It is a super-2 number, since 2×77889833217² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77889833237) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 53 ways as a sum of consecutive naturals, for example, 93955959 + ... + 93956787.

It is an arithmetic number, because the mean of its divisors is an integer number (2436000697).

Almost surely, 2^77889833217 is an apocalyptic number.

It is an amenable number.

77889833217 is a deficient number, since it is larger than the sum of its proper divisors (53654204421).

77889833217 is an equidigital number, since it uses as much as digits as its factorization.

77889833217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1935 (or 1096 counting only the distinct ones).

The product of its digits is 28449792, while the sum is 63.

The spelling of 77889833217 in words is "seventy-seven billion, eight hundred eighty-nine million, eight hundred thirty-three thousand, two hundred seventeen".