209870397 has 24 divisors (see below), whose sum is σ = 334702368. Its totient is φ = 125656800.

The previous prime is 209870393. The next prime is 209870411. The reversal of 209870397 is 793078902.

209870397 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 209870397 - 2² = 209870393 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209870393) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4554 + ... + 20987.

It is an arithmetic number, because the mean of its divisors is an integer number (13945932).

Almost surely, 2^209870397 is an apocalyptic number.

It is an amenable number.

209870397 is a deficient number, since it is larger than the sum of its proper divisors (124831971).

209870397 is a wasteful number, since it uses less digits than its factorization.

209870397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25641 (or 25638 counting only the distinct ones).

The product of its (nonzero) digits is 190512, while the sum is 45.

The square root of 209870397 is about 14486.9043277023. The cubic root of 209870397 is about 594.2698923165.

The spelling of 209870397 in words is "two hundred nine million, eight hundred seventy thousand, three hundred ninety-seven".