16640647 has 2 divisors, whose sum is σ = 16640648. Its totient is φ = 16640646.

The previous prime is 16640621. The next prime is 16640651. The reversal of 16640647 is 74604661.

It is a happy number.

It is a strong prime.

It is an emirp because it is prime and its reverse (74604661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 16640647 - 2¹⁵ = 16607879 is a prime.

It is a super-2 number, since 2×16640647² = 553822265157218, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16640347) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8320323 + 8320324.

It is an arithmetic number, because the mean of its divisors is an integer number (8320324).

Almost surely, 2^16640647 is an apocalyptic number.

16640647 is a deficient number, since it is larger than the sum of its proper divisors (1).

16640647 is an equidigital number, since it uses as much as digits as its factorization.

16640647 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24192, while the sum is 34.

The square root of 16640647 is about 4079.2949145655. The cubic root of 16640647 is about 255.3034807899.

The spelling of 16640647 in words is "sixteen million, six hundred forty thousand, six hundred forty-seven".