16197521 has 2 divisors, whose sum is σ = 16197522. Its totient is φ = 16197520.

The previous prime is 16197499. The next prime is 16197523. The reversal of 16197521 is 12579161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11833600 + 4363921 = 3440^2 + 2089^2 .

It is a cyclic number.

It is not a de Polignac number, because 16197521 - 2¹⁰ = 16196497 is a prime.

Together with 16197523, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (16197523) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8098760 + 8098761.

It is an arithmetic number, because the mean of its divisors is an integer number (8098761).

Almost surely, 2^16197521 is an apocalyptic number.

It is an amenable number.

16197521 is a deficient number, since it is larger than the sum of its proper divisors (1).

16197521 is an equidigital number, since it uses as much as digits as its factorization.

16197521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3780, while the sum is 32.

The square root of 16197521 is about 4024.6143914666. The cubic root of 16197521 is about 253.0168923298.

The spelling of 16197521 in words is "sixteen million, one hundred ninety-seven thousand, five hundred twenty-one".