2091851 has 2 divisors, whose sum is σ = 2091852. Its totient is φ = 2091850.

The previous prime is 2091847. The next prime is 2091863. The reversal of 2091851 is 1581902.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 2091851 - 2² = 2091847 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 2091851.

It is not a weakly prime, because it can be changed into another prime (2091871) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1045925 + 1045926.

It is an arithmetic number, because the mean of its divisors is an integer number (1045926).

2^2091851 is an apocalyptic number.

2091851 is a deficient number, since it is larger than the sum of its proper divisors (1).

2091851 is an equidigital number, since it uses as much as digits as its factorization.

2091851 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 720, while the sum is 26.

The square root of 2091851 is about 1446.3232695355. The cubic root of 2091851 is about 127.8920598805.

It can be divided in two parts, 2091 and 851, that multiplied together give a triangular number (1779441 = T₁₈₈₆).

The spelling of 2091851 in words is "two million, ninety-one thousand, eight hundred fifty-one".