297728721 has 12 divisors (see below), whose sum is σ = 448750848. Its totient is φ = 189855864.

The previous prime is 297728647. The next prime is 297728723. The reversal of 297728721 is 127827792.

It is not a de Polignac number, because 297728721 - 2¹⁸ = 297466577 is a prime.

It is not an unprimeable number, because it can be changed into a prime (297728723) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 718945 + ... + 719358.

It is an arithmetic number, because the mean of its divisors is an integer number (37395904).

Almost surely, 2^297728721 is an apocalyptic number.

It is an amenable number.

297728721 is a deficient number, since it is larger than the sum of its proper divisors (151022127).

297728721 is a wasteful number, since it uses less digits than its factorization.

297728721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1438332 (or 1438329 counting only the distinct ones).

The product of its digits is 197568, while the sum is 45.

The square root of 297728721 is about 17254.8173273437. The cubic root of 297728721 is about 667.7392585888.

The spelling of 297728721 in words is "two hundred ninety-seven million, seven hundred twenty-eight thousand, seven hundred twenty-one".