21252615430265 has 4 divisors (see below), whose sum is σ = 25503138516324. Its totient is φ = 17002092344208.

The previous prime is 21252615430261. The next prime is 21252615430301. The reversal of 21252615430265 is 56203451625212.

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 6998162323216 + 14254453107049 = 2645404^2 + 3775507^2 .

It is a cyclic number.

It is not a de Polignac number, because 21252615430265 - 2² = 21252615430261 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21252615430261) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2125261543022 + ... + 2125261543031.

It is an arithmetic number, because the mean of its divisors is an integer number (6375784629081).

Almost surely, 2^{21252615430265} is an apocalyptic number.

It is an amenable number.

21252615430265 is a deficient number, since it is larger than the sum of its proper divisors (4250523086059).

21252615430265 is an equidigital number, since it uses as much as digits as its factorization.

21252615430265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4250523086058.

The product of its (nonzero) digits is 864000, while the sum is 44.

The spelling of 21252615430265 in words is "twenty-one trillion, two hundred fifty-two billion, six hundred fifteen million, four hundred thirty thousand, two hundred sixty-five".