21880879 has 2 divisors, whose sum is σ = 21880880. Its totient is φ = 21880878.

The previous prime is 21880849. The next prime is 21880919. The reversal of 21880879 is 97808812.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21880879 - 2⁵ = 21880847 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21880829) 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, 10940439 + 10940440.

It is an arithmetic number, because the mean of its divisors is an integer number (10940440).

Almost surely, 2^21880879 is an apocalyptic number.

21880879 is a deficient number, since it is larger than the sum of its proper divisors (1).

21880879 is an equidigital number, since it uses as much as digits as its factorization.

21880879 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 64512, while the sum is 43.

The square root of 21880879 is about 4677.7001827821. The cubic root of 21880879 is about 279.6972876468.

It can be divided in two parts, 2 and 1880879, that added together give a palindrome (1880881).

The spelling of 21880879 in words is "twenty-one million, eight hundred eighty thousand, eight hundred seventy-nine".