21382406 has 8 divisors (see below), whose sum is σ = 32148984. Its totient is φ = 10666080.

The previous prime is 21382393. The next prime is 21382409. The reversal of 21382406 is 60428312.

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 (21382409) 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, 11480 + ... + 13211.

It is an arithmetic number, because the mean of its divisors is an integer number (4018623).

Almost surely, 2^21382406 is an apocalyptic number.

21382406 is a deficient number, since it is larger than the sum of its proper divisors (10766578).

21382406 is a wasteful number, since it uses less digits than its factorization.

21382406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25126.

The product of its (nonzero) digits is 2304, while the sum is 26.

The square root of 21382406 is about 4624.1113740912. Note that the first 3 decimals coincide. The cubic root of 21382406 is about 277.5570036833.

It can be divided in two parts, 2138 and 2406, that multiplied together give a triangular number (5144028 = T₃₂₀₇).

The spelling of 21382406 in words is "twenty-one million, three hundred eighty-two thousand, four hundred six".