91009097281 has 8 divisors (see below), whose sum is σ = 91227988584. Its totient is φ = 90790293120.

The previous prime is 91009097251. The next prime is 91009097351. The reversal of 91009097281 is 18279090019.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 11586584881 + 79422512400 = 107641^2 + 281820^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 91009097281 - 2¹³ = 91009089089 is a prime.

It is a super-2 number, since 2×91009097281² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91009097251) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2385351 + ... + 2423203.

It is an arithmetic number, because the mean of its divisors is an integer number (11403498573).

Almost surely, 2^91009097281 is an apocalyptic number.

It is an amenable number.

91009097281 is a deficient number, since it is larger than the sum of its proper divisors (218891303).

91009097281 is a wasteful number, since it uses less digits than its factorization.

91009097281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43571.

The product of its (nonzero) digits is 81648, while the sum is 46.

The spelling of 91009097281 in words is "ninety-one billion, nine million, ninety-seven thousand, two hundred eighty-one".