21607849 has 2 divisors, whose sum is σ = 21607850. Its totient is φ = 21607848.

The previous prime is 21607841. The next prime is 21607853. The reversal of 21607849 is 94870612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18983449 + 2624400 = 4357^2 + 1620^2 .

It is a cyclic number.

It is not a de Polignac number, because 21607849 - 2³ = 21607841 is a prime.

It is not a weakly prime, because it can be changed into another prime (21607841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10803924 + 10803925.

It is an arithmetic number, because the mean of its divisors is an integer number (10803925).

Almost surely, 2^21607849 is an apocalyptic number.

It is an amenable number.

21607849 is a deficient number, since it is larger than the sum of its proper divisors (1).

21607849 is an equidigital number, since it uses as much as digits as its factorization.

21607849 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24192, while the sum is 37.

The square root of 21607849 is about 4648.4243567041. The cubic root of 21607849 is about 278.5290591082.

The spelling of 21607849 in words is "twenty-one million, six hundred seven thousand, eight hundred forty-nine".