16436821 has 2 divisors, whose sum is σ = 16436822. Its totient is φ = 16436820.

The previous prime is 16436813. The next prime is 16436831. The reversal of 16436821 is 12863461.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16200625 + 236196 = 4025^2 + 486^2 .

It is a cyclic number.

It is not a de Polignac number, because 16436821 - 2³ = 16436813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16436831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8218410 + 8218411.

It is an arithmetic number, because the mean of its divisors is an integer number (8218411).

Almost surely, 2^16436821 is an apocalyptic number.

It is an amenable number.

16436821 is a deficient number, since it is larger than the sum of its proper divisors (1).

16436821 is an equidigital number, since it uses as much as digits as its factorization.

16436821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6912, while the sum is 31.

The square root of 16436821 is about 4054.2349463246. The cubic root of 16436821 is about 254.2568185915.

It can be divided in two parts, 1643 and 6821, that added together give a square (8464 = 92²).

The spelling of 16436821 in words is "sixteen million, four hundred thirty-six thousand, eight hundred twenty-one".