16721297 has 2 divisors, whose sum is σ = 16721298. Its totient is φ = 16721296.

The previous prime is 16721293. The next prime is 16721333. The reversal of 16721297 is 79212761.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15085456 + 1635841 = 3884^2 + 1279^2 .

It is a cyclic number.

It is not a de Polignac number, because 16721297 - 2² = 16721293 is a prime.

It is not a weakly prime, because it can be changed into another prime (16721291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8360648 + 8360649.

It is an arithmetic number, because the mean of its divisors is an integer number (8360649).

Almost surely, 2^16721297 is an apocalyptic number.

It is an amenable number.

16721297 is a deficient number, since it is larger than the sum of its proper divisors (1).

16721297 is an equidigital number, since it uses as much as digits as its factorization.

16721297 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10584, while the sum is 35.

The square root of 16721297 is about 4089.1682528358. The cubic root of 16721297 is about 255.7152646794.

The spelling of 16721297 in words is "sixteen million, seven hundred twenty-one thousand, two hundred ninety-seven".