16646639 has 2 divisors, whose sum is σ = 16646640. Its totient is φ = 16646638.

The previous prime is 16646573. The next prime is 16646657. The reversal of 16646639 is 93664661.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16646639 is a prime.

It is a super-2 number, since 2×16646639² = 554221179992642, which contains 22 as substring.

It is equal to p_1069997 and since 16646639 and 1069997 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 16646596 and 16646605.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16646699) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8323319 + 8323320.

It is an arithmetic number, because the mean of its divisors is an integer number (8323320).

Almost surely, 2^16646639 is an apocalyptic number.

16646639 is a deficient number, since it is larger than the sum of its proper divisors (1).

16646639 is an equidigital number, since it uses as much as digits as its factorization.

16646639 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 139968, while the sum is 41.

The square root of 16646639 is about 4080.0292891106. The cubic root of 16646639 is about 255.3341205216.

The spelling of 16646639 in words is "sixteen million, six hundred forty-six thousand, six hundred thirty-nine".