21179889 has 24 divisors (see below), whose sum is σ = 33321600. Its totient is φ = 12912480.

The previous prime is 21179869. The next prime is 21179891. The reversal of 21179889 is 98897112.

It is not a de Polignac number, because 21179889 - 2⁸ = 21179633 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21179819) 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 in 23 ways as a sum of consecutive naturals, for example, 2824 + ... + 7094.

It is an arithmetic number, because the mean of its divisors is an integer number (1388400).

Almost surely, 2^21179889 is an apocalyptic number.

21179889 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

21179889 is a deficient number, since it is larger than the sum of its proper divisors (12141711).

21179889 is a wasteful number, since it uses less digits than its factorization.

21179889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4325 (or 4322 counting only the distinct ones).

The product of its digits is 72576, while the sum is 45.

The square root of 21179889 is about 4602.1613400662. The cubic root of 21179889 is about 276.6779568303.

The spelling of 21179889 in words is "twenty-one million, one hundred seventy-nine thousand, eight hundred eighty-nine".