21148879 has 2 divisors, whose sum is σ = 21148880. Its totient is φ = 21148878.

The previous prime is 21148861. The next prime is 21148921. The reversal of 21148879 is 97884112.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21148879 - 2⁵ = 21148847 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21148079) 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, 10574439 + 10574440.

It is an arithmetic number, because the mean of its divisors is an integer number (10574440).

Almost surely, 2^21148879 is an apocalyptic number.

21148879 is a deficient number, since it is larger than the sum of its proper divisors (1).

21148879 is an equidigital number, since it uses as much as digits as its factorization.

21148879 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 32256, while the sum is 40.

The square root of 21148879 is about 4598.7910367835. The cubic root of 21148879 is about 276.5428605267.

The spelling of 21148879 in words is "twenty-one million, one hundred forty-eight thousand, eight hundred seventy-nine".