309897397 has 2 divisors, whose sum is σ = 309897398. Its totient is φ = 309897396.

The previous prime is 309897389. The next prime is 309897407. The reversal of 309897397 is 793798903.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 208109476 + 101787921 = 14426^2 + 10089^2 .

It is a cyclic number.

It is not a de Polignac number, because 309897397 - 2³ = 309897389 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (309897317) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 154948698 + 154948699.

It is an arithmetic number, because the mean of its divisors is an integer number (154948699).

Almost surely, 2^309897397 is an apocalyptic number.

It is an amenable number.

309897397 is a deficient number, since it is larger than the sum of its proper divisors (1).

309897397 is an equidigital number, since it uses as much as digits as its factorization.

309897397 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2571912, while the sum is 55.

The square root of 309897397 is about 17603.9028911205. The cubic root of 309897397 is about 676.7152695749.

The spelling of 309897397 in words is "three hundred nine million, eight hundred ninety-seven thousand, three hundred ninety-seven".