21265017 has 4 divisors (see below), whose sum is σ = 28353360. Its totient is φ = 14176676.

The previous prime is 21265001. The next prime is 21265043. The reversal of 21265017 is 71056212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21265017 - 2⁴ = 21265001 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21265067) by changing a digit.

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, 3544167 + ... + 3544172.

It is an arithmetic number, because the mean of its divisors is an integer number (7088340).

Almost surely, 2^21265017 is an apocalyptic number.

It is an amenable number.

21265017 is a deficient number, since it is larger than the sum of its proper divisors (7088343).

21265017 is an equidigital number, since it uses as much as digits as its factorization.

21265017 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7088342.

The product of its (nonzero) digits is 840, while the sum is 24.

The square root of 21265017 is about 4611.4007633256. The cubic root of 21265017 is about 277.0481437865.

The spelling of 21265017 in words is "twenty-one million, two hundred sixty-five thousand, seventeen".