209577349642 has 4 divisors (see below), whose sum is σ = 314366024466. Its totient is φ = 104788674820.

The previous prime is 209577349607. The next prime is 209577349649. The reversal of 209577349642 is 246943775902.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 246943775902 = 2 ⋅123471887951.

It can be written as a sum of positive squares in only one way, i.e., 194630086561 + 14947263081 = 441169^2 + 122259^2 .

It is a Smith number, since the sum of its digits (58) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (209577349649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 52394337409 + ... + 52394337412.

Almost surely, 2^209577349642 is an apocalyptic number.

209577349642 is a deficient number, since it is larger than the sum of its proper divisors (104788674824).

209577349642 is a wasteful number, since it uses less digits than its factorization.

209577349642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104788674823.

The product of its (nonzero) digits is 22861440, while the sum is 58.

The spelling of 209577349642 in words is "two hundred nine billion, five hundred seventy-seven million, three hundred forty-nine thousand, six hundred forty-two".