21388332 has 24 divisors (see below), whose sum is σ = 57035776. Its totient is φ = 6110928.

The previous prime is 21388327. The next prime is 21388333. The reversal of 21388332 is 23388312.

It is a self number, because there is not a number n which added to its sum of digits gives 21388332.

It is not an unprimeable number, because it can be changed into a prime (21388333) 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, 127228 + ... + 127395.

Almost surely, 2^21388332 is an apocalyptic number.

It is an amenable number.

21388332 is an abundant number, since it is smaller than the sum of its proper divisors (35647444).

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

21388332 is a wasteful number, since it uses less digits than its factorization.

21388332 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 254637 (or 254635 counting only the distinct ones).

The product of its digits is 6912, while the sum is 30.

The square root of 21388332 is about 4624.7521014645. The cubic root of 21388332 is about 277.5826423771.

The spelling of 21388332 in words is "twenty-one million, three hundred eighty-eight thousand, three hundred thirty-two".