21340032 has 128 divisors (see below), whose sum is σ = 68739840. Its totient is φ = 5726208.

The previous prime is 21340019. The next prime is 21340051. The reversal of 21340032 is 23004312.

It is a tau number, because it is divible by the number of its divisors (128).

It is a super-2 number, since 2×21340032² = 910793931522048, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21339993 and 21340020.

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 15 ways as a sum of consecutive naturals, for example, 45463 + ... + 45929.

It is an arithmetic number, because the mean of its divisors is an integer number (537030).

Almost surely, 2^21340032 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21340032, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34369920).

21340032 is an abundant number, since it is smaller than the sum of its proper divisors (47399808).

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

21340032 is a wasteful number, since it uses less digits than its factorization.

21340032 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 508 (or 496 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 15.

The square root of 21340032 is about 4619.5272485396. The cubic root of 21340032 is about 277.3735354278.

Adding to 21340032 its reverse (23004312), we get a palindrome (44344344).

The spelling of 21340032 in words is "twenty-one million, three hundred forty thousand, thirty-two".