100890809 has 2 divisors, whose sum is σ = 100890810. Its totient is φ = 100890808.

The previous prime is 100890781. The next prime is 100890841. The reversal of 100890809 is 908098001.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 98565184 + 2325625 = 9928^2 + 1525^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-100890809 is a prime.

It is a super-4 number, since 4×100890809⁴ (a number of 33 digits) contains 4444 as substring.

It is not a weakly prime, because it can be changed into another prime (100890109) 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 as a sum of consecutive naturals, namely, 50445404 + 50445405.

It is an arithmetic number, because the mean of its divisors is an integer number (50445405).

Almost surely, 2^100890809 is an apocalyptic number.

It is an amenable number.

100890809 is a deficient number, since it is larger than the sum of its proper divisors (1).

100890809 is an equidigital number, since it uses as much as digits as its factorization.

100890809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5184, while the sum is 35.

The square root of 100890809 is about 10044.4416967794. The cubic root of 100890809 is about 465.5330673207.

The spelling of 100890809 in words is "one hundred million, eight hundred ninety thousand, eight hundred nine".