21235849 has 2 divisors, whose sum is σ = 21235850. Its totient is φ = 21235848.

The previous prime is 21235843. The next prime is 21235861. The reversal of 21235849 is 94853212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16548624 + 4687225 = 4068^2 + 2165^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21235849 is a prime.

It is a super-2 number, since 2×21235849² = 901922565501602, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21235843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10617924 + 10617925.

It is an arithmetic number, because the mean of its divisors is an integer number (10617925).

Almost surely, 2^21235849 is an apocalyptic number.

It is an amenable number.

21235849 is a deficient number, since it is larger than the sum of its proper divisors (1).

21235849 is an equidigital number, since it uses as much as digits as its factorization.

21235849 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17280, while the sum is 34.

The square root of 21235849 is about 4608.2370815747. The cubic root of 21235849 is about 276.9214154953.

The spelling of 21235849 in words is "twenty-one million, two hundred thirty-five thousand, eight hundred forty-nine".