78891251 has 4 divisors (see below), whose sum is σ = 79841832. Its totient is φ = 77940672.

The previous prime is 78891247. The next prime is 78891269. The reversal of 78891251 is 15219887.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 15219887 = 251 ⋅60637.

It is a cyclic number.

It is not a de Polignac number, because 78891251 - 2² = 78891247 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 78891199 and 78891208.

It is not an unprimeable number, because it can be changed into a prime (78891221) 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, 475166 + ... + 475331.

It is an arithmetic number, because the mean of its divisors is an integer number (19960458).

Almost surely, 2^78891251 is an apocalyptic number.

78891251 is a deficient number, since it is larger than the sum of its proper divisors (950581).

78891251 is an equidigital number, since it uses as much as digits as its factorization.

78891251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 950580.

The product of its digits is 40320, while the sum is 41.

The square root of 78891251 is about 8882.0747013296. The cubic root of 78891251 is about 428.8870642709.

The spelling of 78891251 in words is "seventy-eight million, eight hundred ninety-one thousand, two hundred fifty-one".