21112879 has 2 divisors, whose sum is σ = 21112880. Its totient is φ = 21112878.

The previous prime is 21112867. The next prime is 21112907. The reversal of 21112879 is 97821112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21112879 - 2²¹ = 19015727 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21112879.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21112859) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10556439 + 10556440.

It is an arithmetic number, because the mean of its divisors is an integer number (10556440).

Almost surely, 2^21112879 is an apocalyptic number.

21112879 is a deficient number, since it is larger than the sum of its proper divisors (1).

21112879 is an equidigital number, since it uses as much as digits as its factorization.

21112879 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2016, while the sum is 31.

The square root of 21112879 is about 4594.8752975462. The cubic root of 21112879 is about 276.3858593422.

The spelling of 21112879 in words is "twenty-one million, one hundred twelve thousand, eight hundred seventy-nine".