78315869 has 2 divisors, whose sum is σ = 78315870. Its totient is φ = 78315868.

The previous prime is 78315859. The next prime is 78315883. The reversal of 78315869 is 96851387.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 55323844 + 22992025 = 7438^2 + 4795^2 .

It is a cyclic number.

It is not a de Polignac number, because 78315869 - 2⁸ = 78315613 is a prime.

It is a super-2 number, since 2×78315869² = 12266750674450322, which contains 22 as substring.

It is a Chen prime.

It is equal to p_4576889 and since 78315869 and 4576889 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78315859) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39157934 + 39157935.

It is an arithmetic number, because the mean of its divisors is an integer number (39157935).

Almost surely, 2^78315869 is an apocalyptic number.

It is an amenable number.

78315869 is a deficient number, since it is larger than the sum of its proper divisors (1).

78315869 is an equidigital number, since it uses as much as digits as its factorization.

78315869 is an evil number, because the sum of its binary digits is even.

The product of its digits is 362880, while the sum is 47.

The square root of 78315869 is about 8849.6253593019. The cubic root of 78315869 is about 427.8418436958.

The spelling of 78315869 in words is "seventy-eight million, three hundred fifteen thousand, eight hundred sixty-nine".