21400265 has 4 divisors (see below), whose sum is σ = 25680324. Its totient is φ = 17120208.

The previous prime is 21400219. The next prime is 21400271. The reversal of 21400265 is 56200412.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 12334144 + 9066121 = 3512^2 + 3011^2 .

It is a cyclic number.

It is not a de Polignac number, because 21400265 - 2⁶ = 21400201 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 (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2140022 + ... + 2140031.

It is an arithmetic number, because the mean of its divisors is an integer number (6420081).

Almost surely, 2^21400265 is an apocalyptic number.

It is an amenable number.

21400265 is a deficient number, since it is larger than the sum of its proper divisors (4280059).

21400265 is an equidigital number, since it uses as much as digits as its factorization.

21400265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4280058.

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 21400265 is about 4626.0420447722. The cubic root of 21400265 is about 277.6342558432.

Adding to 21400265 its reverse (56200412), we get a palindrome (77600677).

The spelling of 21400265 in words is "twenty-one million, four hundred thousand, two hundred sixty-five".