21084253 has 2 divisors, whose sum is σ = 21084254. Its totient is φ = 21084252.

The previous prime is 21084227. The next prime is 21084257. The reversal of 21084253 is 35248012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19554084 + 1530169 = 4422^2 + 1237^2 .

It is a cyclic number.

It is not a de Polignac number, because 21084253 - 2¹³ = 21076061 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21084257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10542126 + 10542127.

It is an arithmetic number, because the mean of its divisors is an integer number (10542127).

Almost surely, 2^21084253 is an apocalyptic number.

It is an amenable number.

21084253 is a deficient number, since it is larger than the sum of its proper divisors (1).

21084253 is an equidigital number, since it uses as much as digits as its factorization.

21084253 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1920, while the sum is 25.

The square root of 21084253 is about 4591.7592489154. The cubic root of 21084253 is about 276.2608898064.

The spelling of 21084253 in words is "twenty-one million, eighty-four thousand, two hundred fifty-three".