21005486 has 8 divisors (see below), whose sum is σ = 32878224. Its totient is φ = 10046080.

The previous prime is 21005477. The next prime is 21005503. The reversal of 21005486 is 68450012.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 228275 + ... + 228366.

It is an arithmetic number, because the mean of its divisors is an integer number (4109778).

Almost surely, 2^21005486 is an apocalyptic number.

21005486 is a deficient number, since it is larger than the sum of its proper divisors (11872738).

21005486 is a wasteful number, since it uses less digits than its factorization.

21005486 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 456666.

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 21005486 is about 4583.1742275414. The cubic root of 21005486 is about 275.9164400829.

Adding to 21005486 its reverse (68450012), we get a palindrome (89455498).

The spelling of 21005486 in words is "twenty-one million, five thousand, four hundred eighty-six".