21089896 has 32 divisors (see below), whose sum is σ = 41961600. Its totient is φ = 9915840.

The previous prime is 21089881. The next prime is 21089897. The reversal of 21089896 is 69898012.

It is a happy number.

It is a Smith number, since the sum of its digits (43) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (21089897) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10285 + ... + 12163.

It is an arithmetic number, because the mean of its divisors is an integer number (1311300).

Almost surely, 2^21089896 is an apocalyptic number.

It is an amenable number.

21089896 is a deficient number, since it is larger than the sum of its proper divisors (20871704).

21089896 is a wasteful number, since it uses less digits than its factorization.

21089896 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1969 (or 1965 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 43.

The square root of 21089896 is about 4592.3736781756. The cubic root of 21089896 is about 276.2855338088.

The spelling of 21089896 in words is "twenty-one million, eighty-nine thousand, eight hundred ninety-six".