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91090091 = 113806107
BaseRepresentation
bin1010110110111…
…10110010101011
320100101212010002
411123132302223
5141304340331
613012213215
72154152531
oct533366253
9210355102
1091090091
1147466374
122660a20b
1315b44181
14c152151
157ee49cb
hex56decab

91090091 has 4 divisors (see below), whose sum is σ = 91896312. Its totient is φ = 90283872.

The previous prime is 91090079. The next prime is 91090099. The reversal of 91090091 is 19009019.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19009019 = 76124979.

It is a cyclic number.

It is not a de Polignac number, because 91090091 - 226 = 23981227 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91090099) 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, 402941 + ... + 403166.

It is an arithmetic number, because the mean of its divisors is an integer number (22974078).

Almost surely, 291090091 is an apocalyptic number.

91090091 is a deficient number, since it is larger than the sum of its proper divisors (806221).

91090091 is a wasteful number, since it uses less digits than its factorization.

91090091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 806220.

The product of its (nonzero) digits is 729, while the sum is 29.

The square root of 91090091 is about 9544.1128974882. The cubic root of 91090091 is about 449.9425292861.

The spelling of 91090091 in words is "ninety-one million, ninety thousand, ninety-one".

Divisors: 1 113 806107 91090091