78105683658491 has 4 divisors (see below), whose sum is σ = 78983275609800. Its totient is φ = 77228091707184.

The previous prime is 78105683658463. The next prime is 78105683658551. The reversal of 78105683658491 is 19485638650187.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 78105683658491 - 2²² = 78105679464187 is a prime.

It is a super-2 number, since 2×78105683658491² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78105683658391) 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, 438795975521 + ... + 438795975698.

It is an arithmetic number, because the mean of its divisors is an integer number (19745818902450).

Almost surely, 2^{78105683658491} is an apocalyptic number.

78105683658491 is a deficient number, since it is larger than the sum of its proper divisors (877591951309).

78105683658491 is an equidigital number, since it uses as much as digits as its factorization.

78105683658491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 877591951308.

The product of its (nonzero) digits is 348364800, while the sum is 71.

The spelling of 78105683658491 in words is "seventy-eight trillion, one hundred five billion, six hundred eighty-three million, six hundred fifty-eight thousand, four hundred ninety-one".