16721899 has 2 divisors, whose sum is σ = 16721900. Its totient is φ = 16721898.

The previous prime is 16721833. The next prime is 16721911. The reversal of 16721899 is 99812761.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 16721899 - 2¹⁹ = 16197611 is a prime.

It is not a weakly prime, because it can be changed into another prime (16721819) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8360949 + 8360950.

It is an arithmetic number, because the mean of its divisors is an integer number (8360950).

Almost surely, 2^16721899 is an apocalyptic number.

16721899 is a deficient number, since it is larger than the sum of its proper divisors (1).

16721899 is an equidigital number, since it uses as much as digits as its factorization.

16721899 is an evil number, because the sum of its binary digits is even.

The product of its digits is 54432, while the sum is 43.

The square root of 16721899 is about 4089.2418612745. The cubic root of 16721899 is about 255.7183333956.

The spelling of 16721899 in words is "sixteen million, seven hundred twenty-one thousand, eight hundred ninety-nine".