90208709 has 4 divisors (see below), whose sum is σ = 91222380. Its totient is φ = 89195040.

The previous prime is 90208697. The next prime is 90208717. The reversal of 90208709 is 90780209.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7344100 + 82864609 = 2710^2 + 9103^2 .

It is a cyclic number.

It is not a de Polignac number, because 90208709 - 2⁴ = 90208693 is a prime.

It is a super-2 number, since 2×90208709² = 16275222358893362, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90208309) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 506702 + ... + 506879.

It is an arithmetic number, because the mean of its divisors is an integer number (22805595).

Almost surely, 2^90208709 is an apocalyptic number.

It is an amenable number.

90208709 is a deficient number, since it is larger than the sum of its proper divisors (1013671).

90208709 is a wasteful number, since it uses less digits than its factorization.

90208709 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1013670.

The product of its (nonzero) digits is 9072, while the sum is 35.

The square root of 90208709 is about 9497.8265408461. The cubic root of 90208709 is about 448.4866181529.

The spelling of 90208709 in words is "ninety million, two hundred eight thousand, seven hundred nine".