78009251 has 2 divisors, whose sum is σ = 78009252. Its totient is φ = 78009250.

The previous prime is 78009241. The next prime is 78009257. The reversal of 78009251 is 15290087.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78009251 is a prime.

It is not a weakly prime, because it can be changed into another prime (78009257) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39004625 + 39004626.

It is an arithmetic number, because the mean of its divisors is an integer number (39004626).

Almost surely, 2^78009251 is an apocalyptic number.

78009251 is a deficient number, since it is larger than the sum of its proper divisors (1).

78009251 is an equidigital number, since it uses as much as digits as its factorization.

78009251 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5040, while the sum is 32.

The square root of 78009251 is about 8832.2845855418. The cubic root of 78009251 is about 427.2827591112.

The spelling of 78009251 in words is "seventy-eight million, nine thousand, two hundred fifty-one".