21103879 has 2 divisors, whose sum is σ = 21103880. Its totient is φ = 21103878.

The previous prime is 21103847. The next prime is 21103883. The reversal of 21103879 is 97830112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21103879 - 2⁵ = 21103847 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 21103879.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21103079) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10551939 + 10551940.

It is an arithmetic number, because the mean of its divisors is an integer number (10551940).

Almost surely, 2^21103879 is an apocalyptic number.

21103879 is a deficient number, since it is larger than the sum of its proper divisors (1).

21103879 is an equidigital number, since it uses as much as digits as its factorization.

21103879 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3024, while the sum is 31.

The square root of 21103879 is about 4593.8958412223. The cubic root of 21103879 is about 276.3465811640.

The spelling of 21103879 in words is "twenty-one million, one hundred three thousand, eight hundred seventy-nine".