78162178 has 4 divisors (see below), whose sum is σ = 117243270. Its totient is φ = 39081088.

The previous prime is 78162173. The next prime is 78162193. The reversal of 78162178 is 87126187.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 87126187 = 293 ⋅297359.

It can be written as a sum of positive squares in only one way, i.e., 68508729 + 9653449 = 8277^2 + 3107^2 .

It is a super-2 number, since 2×78162178² = 12218652139407368, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 78162178.

It is not an unprimeable number, because it can be changed into a prime (78162173) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19540543 + ... + 19540546.

Almost surely, 2^78162178 is an apocalyptic number.

78162178 is a deficient number, since it is larger than the sum of its proper divisors (39081092).

78162178 is a wasteful number, since it uses less digits than its factorization.

78162178 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39081091.

The product of its digits is 37632, while the sum is 40.

The square root of 78162178 is about 8840.9376199586. The cubic root of 78162178 is about 427.5617876334.

The spelling of 78162178 in words is "seventy-eight million, one hundred sixty-two thousand, one hundred seventy-eight".