21880919 has 2 divisors, whose sum is σ = 21880920. Its totient is φ = 21880918.

The previous prime is 21880879. The next prime is 21880967. The reversal of 21880919 is 91908812.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21880919 is a prime.

It is a super-2 number, since 2×21880919² = 957549232569122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21880979) 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, 10940459 + 10940460.

It is an arithmetic number, because the mean of its divisors is an integer number (10940460).

Almost surely, 2^21880919 is an apocalyptic number.

21880919 is a deficient number, since it is larger than the sum of its proper divisors (1).

21880919 is an equidigital number, since it uses as much as digits as its factorization.

21880919 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10368, while the sum is 38.

The square root of 21880919 is about 4677.7044583855. The cubic root of 21880919 is about 279.6974580831.

The spelling of 21880919 in words is "twenty-one million, eight hundred eighty thousand, nine hundred nineteen".