78821911 has 8 divisors (see below), whose sum is σ = 95381280. Its totient is φ = 63587328.

The previous prime is 78821893. The next prime is 78821921. The reversal of 78821911 is 11912887.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 78821911 - 2⁵ = 78821879 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 (78821921) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 331066 + ... + 331303.

It is an arithmetic number, because the mean of its divisors is an integer number (11922660).

Almost surely, 2^78821911 is an apocalyptic number.

78821911 is a deficient number, since it is larger than the sum of its proper divisors (16559369).

78821911 is a wasteful number, since it uses less digits than its factorization.

78821911 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 662393.

The product of its digits is 8064, while the sum is 37.

The square root of 78821911 is about 8878.1704759483. The cubic root of 78821911 is about 428.7613733323.

The spelling of 78821911 in words is "seventy-eight million, eight hundred twenty-one thousand, nine hundred eleven".