78841649 has 4 divisors (see below), whose sum is σ = 81384960. Its totient is φ = 76298340.

The previous prime is 78841643. The next prime is 78841657. The reversal of 78841649 is 94614887.

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 78841649 - 2²⁰ = 77793073 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78841643) 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, 1271609 + ... + 1271670.

It is an arithmetic number, because the mean of its divisors is an integer number (20346240).

Almost surely, 2^78841649 is an apocalyptic number.

It is an amenable number.

78841649 is a deficient number, since it is larger than the sum of its proper divisors (2543311).

78841649 is a wasteful number, since it uses less digits than its factorization.

78841649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2543310.

The product of its digits is 387072, while the sum is 47.

The square root of 78841649 is about 8879.2820092618. The cubic root of 78841649 is about 428.7971594294.

The spelling of 78841649 in words is "seventy-eight million, eight hundred forty-one thousand, six hundred forty-nine".