78279121 has 2 divisors, whose sum is σ = 78279122. Its totient is φ = 78279120.

The previous prime is 78279083. The next prime is 78279139. The reversal of 78279121 is 12197287.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 52635025 + 25644096 = 7255^2 + 5064^2 .

It is a cyclic number.

It is not a de Polignac number, because 78279121 - 2²¹ = 76181969 is a prime.

It is a super-2 number, since 2×78279121² = 12255241569065282, which contains 22 as substring.

It is equal to p_4574890 and since 78279121 and 4574890 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (78279521) 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, 39139560 + 39139561.

It is an arithmetic number, because the mean of its divisors is an integer number (39139561).

Almost surely, 2^78279121 is an apocalyptic number.

It is an amenable number.

78279121 is a deficient number, since it is larger than the sum of its proper divisors (1).

78279121 is an equidigital number, since it uses as much as digits as its factorization.

78279121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 14112, while the sum is 37.

The square root of 78279121 is about 8847.5488696022. The cubic root of 78279121 is about 427.7749147663.

It can be divided in two parts, 78279 and 121, that added together give a square (78400 = 280²).

The spelling of 78279121 in words is "seventy-eight million, two hundred seventy-nine thousand, one hundred twenty-one".