209312397 has 64 divisors (see below), whose sum is σ = 373248000. Its totient is φ = 113344704.

The previous prime is 209312393. The next prime is 209312407. The reversal of 209312397 is 793213902.

It is not a de Polignac number, because 209312397 - 2² = 209312393 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209312393) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 777979 + ... + 778247.

It is an arithmetic number, because the mean of its divisors is an integer number (5832000).

Almost surely, 2^209312397 is an apocalyptic number.

209312397 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

209312397 is a deficient number, since it is larger than the sum of its proper divisors (163935603).

209312397 is a wasteful number, since it uses less digits than its factorization.

209312397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 487 (or 481 counting only the distinct ones).

The product of its (nonzero) digits is 20412, while the sum is 36.

The square root of 209312397 is about 14467.6327365606. The cubic root of 209312397 is about 593.7427464746.

The spelling of 209312397 in words is "two hundred nine million, three hundred twelve thousand, three hundred ninety-seven".