209688741 has 6 divisors (see below), whose sum is σ = 302883750. Its totient is φ = 139792488.

The previous prime is 209688737. The next prime is 209688749. The reversal of 209688741 is 147886902.

It can be written as a sum of positive squares in only one way, i.e., 133056225 + 76632516 = 11535^2 + 8754^2 .

It is not a de Polignac number, because 209688741 - 2² = 209688737 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209688749) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 11649366 + ... + 11649383.

It is an arithmetic number, because the mean of its divisors is an integer number (50480625).

Almost surely, 2^209688741 is an apocalyptic number.

It is an amenable number.

209688741 is a deficient number, since it is larger than the sum of its proper divisors (93195009).

209688741 is a wasteful number, since it uses less digits than its factorization.

209688741 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23298755 (or 23298752 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 45.

The square root of 209688741 is about 14480.6333079738. The cubic root of 209688741 is about 594.0983835271.

The spelling of 209688741 in words is "two hundred nine million, six hundred eighty-eight thousand, seven hundred forty-one".