21406038 has 8 divisors (see below), whose sum is σ = 42812088. Its totient is φ = 7135344.

The previous prime is 21406037. The next prime is 21406069. The reversal of 21406038 is 83060412.

It is a happy number.

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

21406038 is an admirable number.

It is a junction number, because it is equal to n+sod(n) for n = 21405999 and 21406017.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21406037) 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 3 ways as a sum of consecutive naturals, for example, 1783831 + ... + 1783842.

It is an arithmetic number, because the mean of its divisors is an integer number (5351511).

Almost surely, 2^21406038 is an apocalyptic number.

21406038 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21406038 is a wasteful number, since it uses less digits than its factorization.

21406038 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3567678.

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 21406038 is about 4626.6659702209. The cubic root of 21406038 is about 277.6592187499.

The spelling of 21406038 in words is "twenty-one million, four hundred six thousand, thirty-eight".