209742890 has 32 divisors (see below), whose sum is σ = 434640384. Its totient is φ = 71383680.

The previous prime is 209742887. The next prime is 209742893. The reversal of 209742890 is 98247902.

It is an interprime number because it is at equal distance from previous prime (209742887) and next prime (209742893).

It is not an unprimeable number, because it can be changed into a prime (209742893) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1346 + ... + 20525.

It is an arithmetic number, because the mean of its divisors is an integer number (13582512).

Almost surely, 2^209742890 is an apocalyptic number.

209742890 is an abundant number, since it is smaller than the sum of its proper divisors (224897494).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

209742890 is a wasteful number, since it uses less digits than its factorization.

209742890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22022.

The product of its (nonzero) digits is 72576, while the sum is 41.

The square root of 209742890 is about 14482.5028914204. The cubic root of 209742890 is about 594.1495181509.

The spelling of 209742890 in words is "two hundred nine million, seven hundred forty-two thousand, eight hundred ninety".