209120521 has 3 divisors (see below), whose sum is σ = 209134983. Its totient is φ = 209106060.

The previous prime is 209120507. The next prime is 209120539. The reversal of 209120521 is 125021902.

The square root of 209120521 is 14461.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 125021902 = 2 ⋅62510951.

It can be written as a sum of positive squares in only one way, i.e., 10310521 + 198810000 = 3211^2 + 14100^2 .

It is a de Polignac number, because none of the positive numbers 2^k-209120521 is a prime.

It is a super-2 number, since 2×209120521² = 87462784606622882, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 209120492 and 209120501.

It is not an unprimeable number, because it can be changed into a prime (209120551) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 7231 + ... + 21691.

It is an arithmetic number, because the mean of its divisors is an integer number (69711661).

Almost surely, 2^209120521 is an apocalyptic number.

209120521 is the 14461-st square number.

209120521 is the 7231-st centered octagonal number.

It is an amenable number.

209120521 is a deficient number, since it is larger than the sum of its proper divisors (14462).

209120521 is an frugal number, since it uses more digits than its factorization.

209120521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28922 (or 14461 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 22.

The cubic root of 209120521 is about 593.5612636541.

The spelling of 209120521 in words is "two hundred nine million, one hundred twenty thousand, five hundred twenty-one".