78243251 has 2 divisors, whose sum is σ = 78243252. Its totient is φ = 78243250.

The previous prime is 78243241. The next prime is 78243257. The reversal of 78243251 is 15234287.

It is a strong prime.

It is an emirp because it is prime and its reverse (15234287) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78243251 is a prime.

It is a super-2 number, since 2×78243251² = 12244012654098002, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (78243257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39121625 + 39121626.

It is an arithmetic number, because the mean of its divisors is an integer number (39121626).

Almost surely, 2^78243251 is an apocalyptic number.

78243251 is a deficient number, since it is larger than the sum of its proper divisors (1).

78243251 is an equidigital number, since it uses as much as digits as its factorization.

78243251 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13440, while the sum is 32.

The square root of 78243251 is about 8845.5215222168. The cubic root of 78243251 is about 427.7095647285.

The spelling of 78243251 in words is "seventy-eight million, two hundred forty-three thousand, two hundred fifty-one".