90805409 has 4 divisors (see below), whose sum is σ = 93936660. Its totient is φ = 87674160.

The previous prime is 90805387. The next prime is 90805433. The reversal of 90805409 is 90450809.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90450809 = 281 ⋅321889.

It can be written as a sum of positive squares in 2 ways, for example, as 34480384 + 56325025 = 5872^2 + 7505^2 .

It is a cyclic number.

It is not a de Polignac number, because 90805409 - 2⁸ = 90805153 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (90805439) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1565582 + ... + 1565639.

It is an arithmetic number, because the mean of its divisors is an integer number (23484165).

Almost surely, 2^90805409 is an apocalyptic number.

It is an amenable number.

90805409 is a deficient number, since it is larger than the sum of its proper divisors (3131251).

90805409 is a wasteful number, since it uses less digits than its factorization.

90805409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3131250.

The product of its (nonzero) digits is 12960, while the sum is 35.

The square root of 90805409 is about 9529.1872161271. The cubic root of 90805409 is about 449.4733080661.

The spelling of 90805409 in words is "ninety million, eight hundred five thousand, four hundred nine".