20821741 has 2 divisors, whose sum is σ = 20821742. Its totient is φ = 20821740.

The previous prime is 20821711. The next prime is 20821747. The reversal of 20821741 is 14712802.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19105641 + 1716100 = 4371^2 + 1310^2 .

It is a cyclic number.

It is not a de Polignac number, because 20821741 - 2⁵ = 20821709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20821747) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10410870 + 10410871.

It is an arithmetic number, because the mean of its divisors is an integer number (10410871).

Almost surely, 2^20821741 is an apocalyptic number.

It is an amenable number.

20821741 is a deficient number, since it is larger than the sum of its proper divisors (1).

20821741 is an equidigital number, since it uses as much as digits as its factorization.

20821741 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 896, while the sum is 25.

The square root of 20821741 is about 4563.0845926851. The cubic root of 20821741 is about 275.1095585505.

The spelling of 20821741 in words is "twenty million, eight hundred twenty-one thousand, seven hundred forty-one".