78909149 has 4 divisors (see below), whose sum is σ = 86082720. Its totient is φ = 71735580.

The previous prime is 78909139. The next prime is 78909151. The reversal of 78909149 is 94190987.

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 a cyclic number.

It is not a de Polignac number, because 78909149 - 2¹⁶ = 78843613 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 (78909119) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3586769 + ... + 3586790.

It is an arithmetic number, because the mean of its divisors is an integer number (21520680).

Almost surely, 2^78909149 is an apocalyptic number.

It is an amenable number.

78909149 is a deficient number, since it is larger than the sum of its proper divisors (7173571).

78909149 is a wasteful number, since it uses less digits than its factorization.

78909149 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7173570.

The product of its (nonzero) digits is 163296, while the sum is 47.

The square root of 78909149 is about 8883.0821790638. The cubic root of 78909149 is about 428.9194955826.

The spelling of 78909149 in words is "seventy-eight million, nine hundred nine thousand, one hundred forty-nine".