16680649 has 2 divisors, whose sum is σ = 16680650. Its totient is φ = 16680648.

The previous prime is 16680619. The next prime is 16680659. The reversal of 16680649 is 94608661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16281225 + 399424 = 4035^2 + 632^2 .

It is a cyclic number.

It is not a de Polignac number, because 16680649 - 2⁵ = 16680617 is a prime.

It is a super-2 number, since 2×16680649² = 556488102122402, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (16680619) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8340324 + 8340325.

It is an arithmetic number, because the mean of its divisors is an integer number (8340325).

Almost surely, 2^16680649 is an apocalyptic number.

It is an amenable number.

16680649 is a deficient number, since it is larger than the sum of its proper divisors (1).

16680649 is an equidigital number, since it uses as much as digits as its factorization.

16680649 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 62208, while the sum is 40.

The square root of 16680649 is about 4084.1950247264. The cubic root of 16680649 is about 255.5078894576.

The spelling of 16680649 in words is "sixteen million, six hundred eighty thousand, six hundred forty-nine".