21339668 has 24 divisors (see below), whose sum is σ = 42998592. Its totient is φ = 9077184.

The previous prime is 21339649. The next prime is 21339671. The reversal of 21339668 is 86693312.

It is a congruent number.

It is an unprimeable number.

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, 1055 + ... + 6617.

It is an arithmetic number, because the mean of its divisors is an integer number (1791608).

Almost surely, 2^21339668 is an apocalyptic number.

21339668 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21339668 is an abundant number, since it is smaller than the sum of its proper divisors (21658924).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21339668 is a wasteful number, since it uses less digits than its factorization.

21339668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5711 (or 5709 counting only the distinct ones).

The product of its digits is 46656, while the sum is 38.

The square root of 21339668 is about 4619.4878504007. The cubic root of 21339668 is about 277.3719583520.

The spelling of 21339668 in words is "twenty-one million, three hundred thirty-nine thousand, six hundred sixty-eight".