21489406 has 32 divisors (see below), whose sum is σ = 35380800. Its totient is φ = 9757440.

The previous prime is 21489401. The next prime is 21489407. The reversal of 21489406 is 60498412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21489401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 118636 + ... + 118816.

It is an arithmetic number, because the mean of its divisors is an integer number (1105650).

Almost surely, 2^21489406 is an apocalyptic number.

21489406 is a deficient number, since it is larger than the sum of its proper divisors (13891394).

21489406 is a wasteful number, since it uses less digits than its factorization.

21489406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 324.

The product of its (nonzero) digits is 13824, while the sum is 34.

The square root of 21489406 is about 4635.6667265885. Note that the first 3 decimals coincide. The cubic root of 21489406 is about 278.0192092035.

The spelling of 21489406 in words is "twenty-one million, four hundred eighty-nine thousand, four hundred six".