78645121 has 4 divisors (see below), whose sum is σ = 78872112. Its totient is φ = 78418132.

The previous prime is 78645097. The next prime is 78645137. The reversal of 78645121 is 12154687.

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 78645121 - 2⁹ = 78644609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78645191) 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, 112975 + ... + 113668.

It is an arithmetic number, because the mean of its divisors is an integer number (19718028).

Almost surely, 2^78645121 is an apocalyptic number.

It is an amenable number.

78645121 is a deficient number, since it is larger than the sum of its proper divisors (226991).

78645121 is a wasteful number, since it uses less digits than its factorization.

78645121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 226990.

The product of its digits is 13440, while the sum is 34.

The square root of 78645121 is about 8868.2084436486. The cubic root of 78645121 is about 428.4405764701.

The spelling of 78645121 in words is "seventy-eight million, six hundred forty-five thousand, one hundred twenty-one".