100809521 has 2 divisors, whose sum is σ = 100809522. Its totient is φ = 100809520.

The previous prime is 100809517. The next prime is 100809557. The reversal of 100809521 is 125908001.

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., 100801600 + 7921 = 10040^2 + 89^2 .

It is a cyclic number.

It is not a de Polignac number, because 100809521 - 2² = 100809517 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (100800521) by changing a digit.

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 as a sum of consecutive naturals, namely, 50404760 + 50404761.

It is an arithmetic number, because the mean of its divisors is an integer number (50404761).

Almost surely, 2^100809521 is an apocalyptic number.

It is an amenable number.

100809521 is a deficient number, since it is larger than the sum of its proper divisors (1).

100809521 is an equidigital number, since it uses as much as digits as its factorization.

100809521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 720, while the sum is 26.

The square root of 100809521 is about 10040.3944643624. The cubic root of 100809521 is about 465.4080066401.

The spelling of 100809521 in words is "one hundred million, eight hundred nine thousand, five hundred twenty-one".