209724489 has 24 divisors (see below), whose sum is σ = 343412160. Its totient is φ = 122267232.

The previous prime is 209724469. The next prime is 209724521. The reversal of 209724489 is 984427902.

It is not a de Polignac number, because 209724489 - 2⁹ = 209723977 is a prime.

It is a super-2 number, since 2×209724489² = 87968722572622242, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (209724469) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 44949 + ... + 49394.

It is an arithmetic number, because the mean of its divisors is an integer number (14308840).

Almost surely, 2^209724489 is an apocalyptic number.

It is an amenable number.

209724489 is a deficient number, since it is larger than the sum of its proper divisors (133687671).

209724489 is a wasteful number, since it uses less digits than its factorization.

209724489 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94381 (or 94378 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 45.

The square root of 209724489 is about 14481.8675936497. The cubic root of 209724489 is about 594.1321424883.

The spelling of 209724489 in words is "two hundred nine million, seven hundred twenty-four thousand, four hundred eighty-nine".