90640 has 40 divisors (see below), whose sum is σ = 232128. Its totient is φ = 32640.

The previous prime is 90631. The next prime is 90641. The reversal of 90640 is 4609.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Smith number, since the sum of its digits (19) coincides with the sum of the digits of its prime factors.

It is a nialpdrome in base 11.

It is not an unprimeable number, because it can be changed into a prime (90641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 829 + ... + 931.

2⁹⁰⁶⁴⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 90640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (116064).

90640 is an abundant number, since it is smaller than the sum of its proper divisors (141488).

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

90640 is a wasteful number, since it uses less digits than its factorization.

90640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127 (or 121 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 19.

The square root of 90640 is about 301.0647770829. The cubic root of 90640 is about 44.9200225512.

It can be divided in two parts, 906 and 40, that added together give a triangular number (946 = T₄₃).

The spelling of 90640 in words is "ninety thousand, six hundred forty".