78257161 has 2 divisors, whose sum is σ = 78257162. Its totient is φ = 78257160.

The previous prime is 78257149. The next prime is 78257177. The reversal of 78257161 is 16175287.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 45481536 + 32775625 = 6744^2 + 5725^2 .

It is an emirp because it is prime and its reverse (16175287) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78257161 - 2²⁵ = 44702729 is a prime.

It is a super-2 number, since 2×78257161² = 12248366495559842, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 78257161.

It is not a weakly prime, because it can be changed into another prime (78257111) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39128580 + 39128581.

It is an arithmetic number, because the mean of its divisors is an integer number (39128581).

Almost surely, 2^78257161 is an apocalyptic number.

It is an amenable number.

78257161 is a deficient number, since it is larger than the sum of its proper divisors (1).

78257161 is an equidigital number, since it uses as much as digits as its factorization.

78257161 is an evil number, because the sum of its binary digits is even.

The product of its digits is 23520, while the sum is 37.

The square root of 78257161 is about 8846.3077608684. The cubic root of 78257161 is about 427.7349091403.

The spelling of 78257161 in words is "seventy-eight million, two hundred fifty-seven thousand, one hundred sixty-one".