78936921 has 24 divisors (see below), whose sum is σ = 132260544. Its totient is φ = 44431200.

The previous prime is 78936919. The next prime is 78936953. The reversal of 78936921 is 12963987.

It is not a de Polignac number, because 78936921 - 2¹ = 78936919 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (78936961) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5130 + ... + 13571.

It is an arithmetic number, because the mean of its divisors is an integer number (5510856).

Almost surely, 2^78936921 is an apocalyptic number.

It is an amenable number.

78936921 is a deficient number, since it is larger than the sum of its proper divisors (53323623).

78936921 is a wasteful number, since it uses less digits than its factorization.

78936921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18781 (or 18778 counting only the distinct ones).

The product of its digits is 163296, while the sum is 45.

The square root of 78936921 is about 8884.6452377121. The cubic root of 78936921 is about 428.9698089500.

The spelling of 78936921 in words is "seventy-eight million, nine hundred thirty-six thousand, nine hundred twenty-one".