16721671 has 2 divisors, whose sum is σ = 16721672. Its totient is φ = 16721670.

The previous prime is 16721657. The next prime is 16721687. The reversal of 16721671 is 17612761.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 16721671 - 2¹¹ = 16719623 is a prime.

It is a super-2 number, since 2×16721671² = 559228562064482, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16721611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8360835 + 8360836.

It is an arithmetic number, because the mean of its divisors is an integer number (8360836).

Almost surely, 2^16721671 is an apocalyptic number.

16721671 is a deficient number, since it is larger than the sum of its proper divisors (1).

16721671 is an equidigital number, since it uses as much as digits as its factorization.

16721671 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3528, while the sum is 31.

The square root of 16721671 is about 4089.2139831513. The cubic root of 16721671 is about 255.7171711662.

The spelling of 16721671 in words is "sixteen million, seven hundred twenty-one thousand, six hundred seventy-one".