21670265 has 8 divisors (see below), whose sum is σ = 26371008. Its totient is φ = 17091760.

The previous prime is 21670219. The next prime is 21670283. The reversal of 21670265 is 56207612.

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

It is not a de Polignac number, because 21670265 - 2⁸ = 21670009 is a prime.

It is a Duffinian 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 7 ways as a sum of consecutive naturals, for example, 30167 + ... + 30876.

It is an arithmetic number, because the mean of its divisors is an integer number (3296376).

Almost surely, 2^21670265 is an apocalyptic number.

It is an amenable number.

21670265 is a deficient number, since it is larger than the sum of its proper divisors (4700743).

21670265 is an equidigital number, since it uses as much as digits as its factorization.

21670265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61119.

The product of its (nonzero) digits is 5040, while the sum is 29.

The square root of 21670265 is about 4655.1331882128. The cubic root of 21670265 is about 278.7969857856.

Adding to 21670265 its reverse (56207612), we get a palindrome (77877877).

The spelling of 21670265 in words is "twenty-one million, six hundred seventy thousand, two hundred sixty-five".