21046245265 has 4 divisors (see below), whose sum is σ = 25255494324. Its totient is φ = 16836996208.

The previous prime is 21046245263. The next prime is 21046245287. The reversal of 21046245265 is 56254264012.

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 12080427921 + 8965817344 = 109911^2 + 94688^2 .

It is a cyclic number.

It is not a de Polignac number, because 21046245265 - 2¹ = 21046245263 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21046245263) 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, 2104624522 + ... + 2104624531.

It is an arithmetic number, because the mean of its divisors is an integer number (6313873581).

Almost surely, 2^21046245265 is an apocalyptic number.

It is an amenable number.

21046245265 is a deficient number, since it is larger than the sum of its proper divisors (4209249059).

21046245265 is an equidigital number, since it uses as much as digits as its factorization.

21046245265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4209249058.

The product of its (nonzero) digits is 115200, while the sum is 37.

The spelling of 21046245265 in words is "twenty-one billion, forty-six million, two hundred forty-five thousand, two hundred sixty-five".