21949853 has 2 divisors, whose sum is σ = 21949854. Its totient is φ = 21949852.

The previous prime is 21949847. The next prime is 21949867. The reversal of 21949853 is 35894912.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17123044 + 4826809 = 4138^2 + 2197^2 .

It is a cyclic number.

It is not a de Polignac number, because 21949853 - 2⁶ = 21949789 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21949853.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21949453) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10974926 + 10974927.

It is an arithmetic number, because the mean of its divisors is an integer number (10974927).

Almost surely, 2^21949853 is an apocalyptic number.

It is an amenable number.

21949853 is a deficient number, since it is larger than the sum of its proper divisors (1).

21949853 is an equidigital number, since it uses as much as digits as its factorization.

21949853 is an evil number, because the sum of its binary digits is even.

The product of its digits is 77760, while the sum is 41.

The square root of 21949853 is about 4685.0670219326. The cubic root of 21949853 is about 279.9908713010.

The spelling of 21949853 in words is "twenty-one million, nine hundred forty-nine thousand, eight hundred fifty-three".