21208270 has 8 divisors (see below), whose sum is σ = 38174904. Its totient is φ = 8483304.

The previous prime is 21208259. The next prime is 21208349. The reversal of 21208270 is 7280212.

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 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, 1060404 + ... + 1060423.

It is an arithmetic number, because the mean of its divisors is an integer number (4771863).

Almost surely, 2^21208270 is an apocalyptic number.

21208270 is a deficient number, since it is larger than the sum of its proper divisors (16966634).

21208270 is a wasteful number, since it uses less digits than its factorization.

21208270 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2120834.

The product of its (nonzero) digits is 448, while the sum is 22.

The square root of 21208270 is about 4605.2437503350. The cubic root of 21208270 is about 276.8014842687.

Adding to 21208270 its reverse (7280212), we get a palindrome (28488482).

The spelling of 21208270 in words is "twenty-one million, two hundred eight thousand, two hundred seventy".