78318091 has 4 divisors (see below), whose sum is σ = 79125592. Its totient is φ = 77510592.

The previous prime is 78318089. The next prime is 78318137. The reversal of 78318091 is 19081387.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 78318091 - 2¹ = 78318089 is a prime.

It is a super-2 number, since 2×78318091² = 12267446755768562, which contains 22 as substring.

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 78318091.

It is not an unprimeable number, because it can be changed into a prime (78319091) 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 3 ways as a sum of consecutive naturals, for example, 403605 + ... + 403798.

It is an arithmetic number, because the mean of its divisors is an integer number (19781398).

Almost surely, 2^78318091 is an apocalyptic number.

78318091 is a deficient number, since it is larger than the sum of its proper divisors (807501).

78318091 is an equidigital number, since it uses as much as digits as its factorization.

78318091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 807500.

The product of its (nonzero) digits is 12096, while the sum is 37.

The square root of 78318091 is about 8849.7509004491. The cubic root of 78318091 is about 427.8458899409.

The spelling of 78318091 in words is "seventy-eight million, three hundred eighteen thousand, ninety-one".