21766853 has 2 divisors, whose sum is σ = 21766854. Its totient is φ = 21766852.

The previous prime is 21766831. The next prime is 21766873. The reversal of 21766853 is 35866712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19070689 + 2696164 = 4367^2 + 1642^2 .

It is a cyclic number.

It is not a de Polignac number, because 21766853 - 2⁸ = 21766597 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21766873) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10883426 + 10883427.

It is an arithmetic number, because the mean of its divisors is an integer number (10883427).

Almost surely, 2^21766853 is an apocalyptic number.

It is an amenable number.

21766853 is a deficient number, since it is larger than the sum of its proper divisors (1).

21766853 is an equidigital number, since it uses as much as digits as its factorization.

21766853 is an evil number, because the sum of its binary digits is even.

The product of its digits is 60480, while the sum is 38.

The square root of 21766853 is about 4665.4960079288. The cubic root of 21766853 is about 279.2105868474.

The spelling of 21766853 in words is "twenty-one million, seven hundred sixty-six thousand, eight hundred fifty-three".