209973539 has 4 divisors (see below), whose sum is σ = 211484280. Its totient is φ = 208462800.

The previous prime is 209973499. The next prime is 209973551. The reversal of 209973539 is 935379902.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 935379902 = 2 ⋅467689951.

It is a cyclic number.

It is not a de Polignac number, because 209973539 - 2¹² = 209969443 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 209973493 and 209973502.

It is not an unprimeable number, because it can be changed into a prime (209973559) 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, 755162 + ... + 755439.

It is an arithmetic number, because the mean of its divisors is an integer number (52871070).

Almost surely, 2^209973539 is an apocalyptic number.

209973539 is a deficient number, since it is larger than the sum of its proper divisors (1510741).

209973539 is a wasteful number, since it uses less digits than its factorization.

209973539 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1510740.

The product of its (nonzero) digits is 459270, while the sum is 47.

The square root of 209973539 is about 14490.4637261890. The cubic root of 209973539 is about 594.3672288120.

The spelling of 209973539 in words is "two hundred nine million, nine hundred seventy-three thousand, five hundred thirty-nine".