209098821 has 4 divisors (see below), whose sum is σ = 278798432. Its totient is φ = 139399212.

The previous prime is 209098801. The next prime is 209098823. The reversal of 209098821 is 128890902.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 209098821 - 2⁷ = 209098693 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 209098821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209098823) 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, 34849801 + ... + 34849806.

It is an arithmetic number, because the mean of its divisors is an integer number (69699608).

Almost surely, 2^209098821 is an apocalyptic number.

It is an amenable number.

209098821 is a deficient number, since it is larger than the sum of its proper divisors (69699611).

209098821 is an equidigital number, since it uses as much as digits as its factorization.

209098821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69699610.

The product of its (nonzero) digits is 20736, while the sum is 39.

The square root of 209098821 is about 14460.2496866410. The cubic root of 209098821 is about 593.5407320728.

The spelling of 209098821 in words is "two hundred nine million, ninety-eight thousand, eight hundred twenty-one".