21246257 has 8 divisors (see below), whose sum is σ = 22005984. Its totient is φ = 20498688.

The previous prime is 21246229. The next prime is 21246263. The reversal of 21246257 is 75264212.

It is a happy number.

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 21246257 - 2⁶ = 21246193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21246287) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 593 + ... + 6545.

It is an arithmetic number, because the mean of its divisors is an integer number (2750748).

Almost surely, 2^21246257 is an apocalyptic number.

It is an amenable number.

21246257 is a deficient number, since it is larger than the sum of its proper divisors (759727).

21246257 is an equidigital number, since it uses as much as digits as its factorization.

21246257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6079.

The product of its digits is 6720, while the sum is 29.

The square root of 21246257 is about 4609.3662254154. The cubic root of 21246257 is about 276.9666491841.

The spelling of 21246257 in words is "twenty-one million, two hundred forty-six thousand, two hundred fifty-seven".