21641406 has 8 divisors (see below), whose sum is σ = 43282824. Its totient is φ = 7213800.

The previous prime is 21641393. The next prime is 21641467. The reversal of 21641406 is 60414612.

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

21641406 is an admirable number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1803445 + ... + 1803456.

It is an arithmetic number, because the mean of its divisors is an integer number (5410353).

Almost surely, 2^21641406 is an apocalyptic number.

21641406 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.

21641406 is a wasteful number, since it uses less digits than its factorization.

21641406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3606906.

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

The square root of 21641406 is about 4652.0324590441. The cubic root of 21641406 is about 278.6731697874.

It can be divided in two parts, 2164 and 1406, that added together give a triangular number (3570 = T₈₄).

The spelling of 21641406 in words is "twenty-one million, six hundred forty-one thousand, four hundred six".