90100009 has 2 divisors, whose sum is σ = 90100010. Its totient is φ = 90100008.

The previous prime is 90099991. The next prime is 90100057. The reversal of 90100009 is 90000109.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 86211225 + 3888784 = 9285^2 + 1972^2 .

It is an emirp because it is prime and its reverse (90000109) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 90100009 - 2²¹ = 88002857 is a prime.

It is not a weakly prime, because it can be changed into another prime (90100079) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45050004 + 45050005.

It is an arithmetic number, because the mean of its divisors is an integer number (45050005).

Almost surely, 2^90100009 is an apocalyptic number.

It is an amenable number.

90100009 is a deficient number, since it is larger than the sum of its proper divisors (1).

90100009 is an equidigital number, since it uses as much as digits as its factorization.

90100009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 81, while the sum is 19.

The square root of 90100009 is about 9492.1024541458. The cubic root of 90100009 is about 448.3064061009.

The spelling of 90100009 in words is "ninety million, one hundred thousand, nine".