21965249 has 2 divisors, whose sum is σ = 21965250. Its totient is φ = 21965248.

The previous prime is 21965243. The next prime is 21965351. The reversal of 21965249 is 94256912.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19963024 + 2002225 = 4468^2 + 1415^2 .

It is a cyclic number.

It is not a de Polignac number, because 21965249 - 2⁴ = 21965233 is a prime.

It is not a weakly prime, because it can be changed into another prime (21965243) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10982624 + 10982625.

It is an arithmetic number, because the mean of its divisors is an integer number (10982625).

Almost surely, 2^21965249 is an apocalyptic number.

It is an amenable number.

21965249 is a deficient number, since it is larger than the sum of its proper divisors (1).

21965249 is an equidigital number, since it uses as much as digits as its factorization.

21965249 is an evil number, because the sum of its binary digits is even.

The product of its digits is 38880, while the sum is 38.

The square root of 21965249 is about 4686.7098267335. The cubic root of 21965249 is about 280.0563194534.

The spelling of 21965249 in words is "twenty-one million, nine hundred sixty-five thousand, two hundred forty-nine".