16991851 has 2 divisors, whose sum is σ = 16991852. Its totient is φ = 16991850.

The previous prime is 16991809. The next prime is 16991861. The reversal of 16991851 is 15819961.

It is a strong prime.

It is an emirp because it is prime and its reverse (15819961) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 16991851 - 2²¹ = 14894699 is a prime.

It is not a weakly prime, because it can be changed into another prime (16991861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8495925 + 8495926.

It is an arithmetic number, because the mean of its divisors is an integer number (8495926).

Almost surely, 2^16991851 is an apocalyptic number.

16991851 is a deficient number, since it is larger than the sum of its proper divisors (1).

16991851 is an equidigital number, since it uses as much as digits as its factorization.

16991851 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 19440, while the sum is 40.

The square root of 16991851 is about 4122.1172957595. The cubic root of 16991851 is about 257.0870674529.

The spelling of 16991851 in words is "sixteen million, nine hundred ninety-one thousand, eight hundred fifty-one".