21711853 has 2 divisors, whose sum is σ = 21711854. Its totient is φ = 21711852.

The previous prime is 21711841. The next prime is 21711857. The reversal of 21711853 is 35811712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12938409 + 8773444 = 3597^2 + 2962^2 .

It is a cyclic number.

It is not a de Polignac number, because 21711853 - 2¹⁷ = 21580781 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21711857) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10855926 + 10855927.

It is an arithmetic number, because the mean of its divisors is an integer number (10855927).

Almost surely, 2^21711853 is an apocalyptic number.

It is an amenable number.

21711853 is a deficient number, since it is larger than the sum of its proper divisors (1).

21711853 is an equidigital number, since it uses as much as digits as its factorization.

21711853 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1680, while the sum is 28.

The square root of 21711853 is about 4659.5979440291. The cubic root of 21711853 is about 278.9752207966.

The spelling of 21711853 in words is "twenty-one million, seven hundred eleven thousand, eight hundred fifty-three".