78291247 has 2 divisors, whose sum is σ = 78291248. Its totient is φ = 78291246.

The previous prime is 78291209. The next prime is 78291277. The reversal of 78291247 is 74219287.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 78291247 - 2²³ = 69902639 is a prime.

It is a super-2 number, since 2×78291247² = 12259038713630018, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78291277) 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, 39145623 + 39145624.

It is an arithmetic number, because the mean of its divisors is an integer number (39145624).

Almost surely, 2^78291247 is an apocalyptic number.

78291247 is a deficient number, since it is larger than the sum of its proper divisors (1).

78291247 is an equidigital number, since it uses as much as digits as its factorization.

78291247 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 56448, while the sum is 40.

The square root of 78291247 is about 8848.2341176079. The cubic root of 78291247 is about 427.7970020983.

It can be divided in two parts, 782 and 91247, that added together give a palindrome (92029).

The spelling of 78291247 in words is "seventy-eight million, two hundred ninety-one thousand, two hundred forty-seven".