209681942 has 4 divisors (see below), whose sum is σ = 314522916. Its totient is φ = 104840970.

The previous prime is 209681911. The next prime is 209681947. The reversal of 209681942 is 249186902.

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

It is a self number, because there is not a number n which added to its sum of digits gives 209681942.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209681947) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 52420484 + ... + 52420487.

It is an arithmetic number, because the mean of its divisors is an integer number (78630729).

Almost surely, 2^209681942 is an apocalyptic number.

209681942 is a deficient number, since it is larger than the sum of its proper divisors (104840974).

209681942 is a wasteful number, since it uses less digits than its factorization.

209681942 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104840973.

The product of its (nonzero) digits is 62208, while the sum is 41.

The square root of 209681942 is about 14480.3985442390. The cubic root of 209681942 is about 594.0919623930.

The spelling of 209681942 in words is "two hundred nine million, six hundred eighty-one thousand, nine hundred forty-two".