91939321840 has 20 divisors (see below), whose sum is σ = 213758923464. Its totient is φ = 36775728704.

The previous prime is 91939321823. The next prime is 91939321849. The reversal of 91939321840 is 4812393919.

It is a tau number, because it is divible by the number of its divisors (20).

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 pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 574620682 + ... + 574620841.

Almost surely, 2^91939321840 is an apocalyptic number.

It is an amenable number.

91939321840 is an abundant number, since it is smaller than the sum of its proper divisors (121819601624).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

91939321840 is a wasteful number, since it uses less digits than its factorization.

91939321840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1149241536 (or 1149241530 counting only the distinct ones).

The product of its (nonzero) digits is 419904, while the sum is 49.

The spelling of 91939321840 in words is "ninety-one billion, nine hundred thirty-nine million, three hundred twenty-one thousand, eight hundred forty".