21142265 has 16 divisors (see below), whose sum is σ = 26199936. Its totient is φ = 16368000.

The previous prime is 21142259. The next prime is 21142273. The reversal of 21142265 is 56224112.

It is a happy number.

It is not a de Polignac number, because 21142265 - 2⁶ = 21142201 is a prime.

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 21142265.

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 15 ways as a sum of consecutive naturals, for example, 30614 + ... + 31296.

It is an arithmetic number, because the mean of its divisors is an integer number (1637496).

Almost surely, 2^21142265 is an apocalyptic number.

It is an amenable number.

21142265 is a deficient number, since it is larger than the sum of its proper divisors (5057671).

21142265 is a wasteful number, since it uses less digits than its factorization.

21142265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 880.

The product of its digits is 960, while the sum is 23.

The square root of 21142265 is about 4598.0718785160. The cubic root of 21142265 is about 276.5140292873.

Adding to 21142265 its reverse (56224112), we get a palindrome (77366377).

The spelling of 21142265 in words is "twenty-one million, one hundred forty-two thousand, two hundred sixty-five".