91841120809 has 3 divisors (see below), whose sum is σ = 91841423863. Its totient is φ = 91840817756.

The previous prime is 91841120759. The next prime is 91841120821. The reversal of 91841120809 is 90802114819.

It is a happy number.

The square root of 91841120809 is 303053.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 87240483225 + 4600637584 = 295365^2 + 67828^2 .

It is a de Polignac number, because none of the positive numbers 2^k-91841120809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91841120869) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 151527 + ... + 454579.

Almost surely, 2^91841120809 is an apocalyptic number.

91841120809 is the 303053-rd square number.

91841120809 is the 151527-th centered octagonal number.

It is an amenable number.

91841120809 is a deficient number, since it is larger than the sum of its proper divisors (303054).

91841120809 is an frugal number, since it uses more digits than its factorization.

91841120809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 606106 (or 303053 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 43.

The spelling of 91841120809 in words is "ninety-one billion, eight hundred forty-one million, one hundred twenty thousand, eight hundred nine".