21258205 has 8 divisors (see below), whose sum is σ = 25556832. Its totient is φ = 16975248.

The previous prime is 21258199. The next prime is 21258253. The reversal of 21258205 is 50285212.

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

It is a cyclic number.

It is not a de Polignac number, because 21258205 - 2⁵ = 21258173 is a prime.

It is a super-2 number, since 2×21258205² = 903822559644050, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21258205.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 687 + ... + 6556.

It is an arithmetic number, because the mean of its divisors is an integer number (3194604).

Almost surely, 2^21258205 is an apocalyptic number.

It is an amenable number.

21258205 is a deficient number, since it is larger than the sum of its proper divisors (4298627).

21258205 is an equidigital number, since it uses as much as digits as its factorization.

21258205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7835.

The product of its (nonzero) digits is 1600, while the sum is 25.

The square root of 21258205 is about 4610.6620999592. The cubic root of 21258205 is about 277.0185575806.

The spelling of 21258205 in words is "twenty-one million, two hundred fifty-eight thousand, two hundred five".