209861435389 has 4 divisors (see below), whose sum is σ = 222206225724. Its totient is φ = 197516645056.

The previous prime is 209861435383. The next prime is 209861435401. The reversal of 209861435389 is 983534168902.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 84940188025 + 124921247364 = 291445^2 + 353442^2 .

It is a cyclic number.

It is not a de Polignac number, because 209861435389 - 2¹³ = 209861427197 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209861435383) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6172395142 + ... + 6172395175.

It is an arithmetic number, because the mean of its divisors is an integer number (55551556431).

Almost surely, 2^209861435389 is an apocalyptic number.

It is an amenable number.

209861435389 is a deficient number, since it is larger than the sum of its proper divisors (12344790335).

209861435389 is a wasteful number, since it uses less digits than its factorization.

209861435389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12344790334.

The product of its (nonzero) digits is 11197440, while the sum is 58.

The spelling of 209861435389 in words is "two hundred nine billion, eight hundred sixty-one million, four hundred thirty-five thousand, three hundred eighty-nine".