78358121 has 2 divisors, whose sum is σ = 78358122. Its totient is φ = 78358120.

The previous prime is 78358103. The next prime is 78358153. The reversal of 78358121 is 12185387.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 78145600 + 212521 = 8840^2 + 461^2 .

It is a cyclic number.

It is not a de Polignac number, because 78358121 - 2¹⁴ = 78341737 is a prime.

It is a super-2 number, since 2×78358121² = 12279990253301282, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (78351121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39179060 + 39179061.

It is an arithmetic number, because the mean of its divisors is an integer number (39179061).

Almost surely, 2^78358121 is an apocalyptic number.

It is an amenable number.

78358121 is a deficient number, since it is larger than the sum of its proper divisors (1).

78358121 is an equidigital number, since it uses as much as digits as its factorization.

78358121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13440, while the sum is 35.

The square root of 78358121 is about 8852.0122571085. The cubic root of 78358121 is about 427.9187711600.

The spelling of 78358121 in words is "seventy-eight million, three hundred fifty-eight thousand, one hundred twenty-one".