78311161 has 2 divisors, whose sum is σ = 78311162. Its totient is φ = 78311160.

The previous prime is 78311153. The next prime is 78311171. The reversal of 78311161 is 16111387.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 75690000 + 2621161 = 8700^2 + 1619^2 .

It is an emirp because it is prime and its reverse (16111387) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78311161 - 2³ = 78311153 is a prime.

It is a super-2 number, since 2×78311161² = 12265275874335842, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (78311131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39155580 + 39155581.

It is an arithmetic number, because the mean of its divisors is an integer number (39155581).

Almost surely, 2^78311161 is an apocalyptic number.

It is an amenable number.

78311161 is a deficient number, since it is larger than the sum of its proper divisors (1).

78311161 is an equidigital number, since it uses as much as digits as its factorization.

78311161 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1008, while the sum is 28.

The square root of 78311161 is about 8849.3593553432. The cubic root of 78311161 is about 427.8332702109.

The spelling of 78311161 in words is "seventy-eight million, three hundred eleven thousand, one hundred sixty-one".