78118221 has 4 divisors (see below), whose sum is σ = 104157632. Its totient is φ = 52078812.

The previous prime is 78118217. The next prime is 78118223. The reversal of 78118221 is 12281187.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 78118221 - 2² = 78118217 is a prime.

It is a super-2 number, since 2×78118221² = 12204912904409682, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78118223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13019701 + ... + 13019706.

It is an arithmetic number, because the mean of its divisors is an integer number (26039408).

Almost surely, 2^78118221 is an apocalyptic number.

It is an amenable number.

78118221 is a deficient number, since it is larger than the sum of its proper divisors (26039411).

78118221 is a wasteful number, since it uses less digits than its factorization.

78118221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26039410.

The product of its digits is 1792, while the sum is 30.

The square root of 78118221 is about 8838.4512783632. The cubic root of 78118221 is about 427.4816215895.

The spelling of 78118221 in words is "seventy-eight million, one hundred eighteen thousand, two hundred twenty-one".