91840443251 has 4 divisors (see below), whose sum is σ = 94080454104. Its totient is φ = 89600432400.

The previous prime is 91840443239. The next prime is 91840443281. The reversal of 91840443251 is 15234404819.

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

It is a de Polignac number, because none of the positive numbers 2^k-91840443251 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (41), and also a Moran number because the ratio is a prime number: 2240010811 = 91840443251 / (9 + 1 + 8 + 4 + 0 + 4 + 4 + 3 + 2 + 5 + 1).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 91840443199 and 91840443208.

It is not an unprimeable number, because it can be changed into a prime (91840443281) 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, 1120005365 + ... + 1120005446.

It is an arithmetic number, because the mean of its divisors is an integer number (23520113526).

Almost surely, 2^91840443251 is an apocalyptic number.

91840443251 is a deficient number, since it is larger than the sum of its proper divisors (2240010853).

91840443251 is a wasteful number, since it uses less digits than its factorization.

91840443251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2240010852.

The product of its (nonzero) digits is 138240, while the sum is 41.

The spelling of 91840443251 in words is "ninety-one billion, eight hundred forty million, four hundred forty-three thousand, two hundred fifty-one".