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90000000 = 273257

90000000 has 192 divisors, whose sum is σ = 323729640. Its totient is φ = 24000000.

The previous prime is 89999999. The next prime is 90000049. The reversal of 90000000 is 9.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in 4 ways, for example, as 54287424 + 35712576 = 7368^2 + 5976^2 .

It is a tau number, because it is divible by the number of its divisors (192).

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.

It is a nialpdrome in base 10.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 17999998 + ... + 18000002.

Almost surely, 290000000 is an apocalyptic number.

90000000 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 90000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (161864820).

90000000 is an abundant number, since it is smaller than the sum of its proper divisors (233729640).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

90000000 is an frugal number, since it uses more digits than its factorization.

90000000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55 (or 10 counting only the distinct ones).

The product of its (nonzero) digits is 9, while the sum is 9.

The square root of 90000000 is about 9486.8329805051. The cubic root of 90000000 is about 448.1404746557.

The spelling of 90000000 in words is "ninety million", and thus it is an aban number and an uban number.