78340891 has 4 divisors (see below), whose sum is σ = 78677352. Its totient is φ = 78004432.

The previous prime is 78340859. The next prime is 78340901. The reversal of 78340891 is 19804387.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19804387 = 541 ⋅36607.

It is a cyclic number.

It is not a de Polignac number, because 78340891 - 2⁵ = 78340859 is a prime.

It is a super-2 number, since 2×78340891² = 12274590405347762, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78340091) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 167881 + ... + 168346.

It is an arithmetic number, because the mean of its divisors is an integer number (19669338).

Almost surely, 2^78340891 is an apocalyptic number.

78340891 is a deficient number, since it is larger than the sum of its proper divisors (336461).

78340891 is a wasteful number, since it uses less digits than its factorization.

78340891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 336460.

The product of its (nonzero) digits is 48384, while the sum is 40.

The square root of 78340891 is about 8851.0389785607. The cubic root of 78340891 is about 427.8874041457.

The spelling of 78340891 in words is "seventy-eight million, three hundred forty thousand, eight hundred ninety-one".