78821101 has 12 divisors (see below), whose sum is σ = 86067900. Its totient is φ = 72088128.

The previous prime is 78821077. The next prime is 78821117. The reversal of 78821101 is 10112887.

It can be written as a sum of positive squares in 2 ways, for example, as 33582025 + 45239076 = 5795^2 + 6726^2 .

It is a de Polignac number, because none of the positive numbers 2^k-78821101 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 78821101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78821131) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6705 + ... + 14233.

It is an arithmetic number, because the mean of its divisors is an integer number (7172325).

Almost surely, 2^78821101 is an apocalyptic number.

It is an amenable number.

78821101 is a deficient number, since it is larger than the sum of its proper divisors (7246799).

78821101 is a wasteful number, since it uses less digits than its factorization.

78821101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7596 (or 7577 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 28.

The square root of 78821101 is about 8878.1248583245. The cubic root of 78821101 is about 428.7599046294.

Adding to 78821101 its reverse (10112887), we get a palindrome (88933988).

The spelling of 78821101 in words is "seventy-eight million, eight hundred twenty-one thousand, one hundred one".