21913849 has 2 divisors, whose sum is σ = 21913850. Its totient is φ = 21913848.

The previous prime is 21913831. The next prime is 21913861. The reversal of 21913849 is 94831912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21902400 + 11449 = 4680^2 + 107^2 .

It is a cyclic number.

It is not a de Polignac number, because 21913849 - 2⁵ = 21913817 is a prime.

It is not a weakly prime, because it can be changed into another prime (21913819) 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, 10956924 + 10956925.

It is an arithmetic number, because the mean of its divisors is an integer number (10956925).

Almost surely, 2^21913849 is an apocalyptic number.

It is an amenable number.

21913849 is a deficient number, since it is larger than the sum of its proper divisors (1).

21913849 is an equidigital number, since it uses as much as digits as its factorization.

21913849 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15552, while the sum is 37.

The square root of 21913849 is about 4681.2230239543. The cubic root of 21913849 is about 279.8376993087.

The spelling of 21913849 in words is "twenty-one million, nine hundred thirteen thousand, eight hundred forty-nine".