209397742 has 8 divisors (see below), whose sum is σ = 321757632. Its totient is φ = 102145200.

The previous prime is 209397733. The next prime is 209397743. The reversal of 209397742 is 247793902.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209397743) 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, 1276734 + ... + 1276897.

It is an arithmetic number, because the mean of its divisors is an integer number (40219704).

Almost surely, 2^209397742 is an apocalyptic number.

209397742 is a deficient number, since it is larger than the sum of its proper divisors (112359890).

209397742 is a wasteful number, since it uses less digits than its factorization.

209397742 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2553674.

The product of its (nonzero) digits is 190512, while the sum is 43.

The square root of 209397742 is about 14470.5819509790. The cubic root of 209397742 is about 593.8234330303.

It can be divided in two parts, 20939774 and 2, that added together give a square (20939776 = 4576²).

The spelling of 209397742 in words is "two hundred nine million, three hundred ninety-seven thousand, seven hundred forty-two".