78191893 has 8 divisors (see below), whose sum is σ = 85222368. Its totient is φ = 71306544.

The previous prime is 78191873. The next prime is 78191899. The reversal of 78191893 is 39819187.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78191893 is a prime.

It is a super-2 number, since 2×78191893² = 12227944261846898, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78191899) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 35155 + ... + 37312.

It is an arithmetic number, because the mean of its divisors is an integer number (10652796).

Almost surely, 2^78191893 is an apocalyptic number.

It is an amenable number.

78191893 is a deficient number, since it is larger than the sum of its proper divisors (7030475).

78191893 is a wasteful number, since it uses less digits than its factorization.

78191893 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72563.

The product of its digits is 108864, while the sum is 46.

The square root of 78191893 is about 8842.6179946891. The cubic root of 78191893 is about 427.6159629783.

The spelling of 78191893 in words is "seventy-eight million, one hundred ninety-one thousand, eight hundred ninety-three".