21330406 has 8 divisors (see below), whose sum is σ = 32051880. Its totient is φ = 10646448.

The previous prime is 21330403. The next prime is 21330443. The reversal of 21330406 is 60403312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21330403) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7911 + ... + 10258.

It is an arithmetic number, because the mean of its divisors is an integer number (4006485).

Almost surely, 2^21330406 is an apocalyptic number.

21330406 is a deficient number, since it is larger than the sum of its proper divisors (10721474).

21330406 is a wasteful number, since it uses less digits than its factorization.

21330406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18758.

The product of its (nonzero) digits is 432, while the sum is 19.

The square root of 21330406 is about 4618.4852495163. The cubic root of 21330406 is about 277.3318235377.

Adding to 21330406 its reverse (60403312), we get a palindrome (81733718).

It can be divided in two parts, 21330 and 406, that added together give a triangular number (21736 = T₂₀₈).

The spelling of 21330406 in words is "twenty-one million, three hundred thirty thousand, four hundred six".