91939321847 has 4 divisors (see below), whose sum is σ = 95109643320. Its totient is φ = 88769000376.

The previous prime is 91939321823. The next prime is 91939321849. The reversal of 91939321847 is 74812393919.

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 91939321847 - 2¹² = 91939317751 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 91939321792 and 91939321801.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91939321849) 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, 1585160693 + ... + 1585160750.

It is an arithmetic number, because the mean of its divisors is an integer number (23777410830).

Almost surely, 2^91939321847 is an apocalyptic number.

91939321847 is a deficient number, since it is larger than the sum of its proper divisors (3170321473).

91939321847 is a wasteful number, since it uses less digits than its factorization.

91939321847 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3170321472.

The product of its digits is 2939328, while the sum is 56.

The spelling of 91939321847 in words is "ninety-one billion, nine hundred thirty-nine million, three hundred twenty-one thousand, eight hundred forty-seven".