21288851345 has 4 divisors (see below), whose sum is σ = 25546621620. Its totient is φ = 17031081072.

The previous prime is 21288851327. The next prime is 21288851383. The reversal of 21288851345 is 54315888212.

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 4384691089 + 16904160256 = 66217^2 + 130016^2 .

It is a cyclic number.

It is not a de Polignac number, because 21288851345 - 2²⁴ = 21272074129 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21288851345.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2128885130 + ... + 2128885139.

It is an arithmetic number, because the mean of its divisors is an integer number (6386655405).

Almost surely, 2^21288851345 is an apocalyptic number.

It is an amenable number.

21288851345 is a deficient number, since it is larger than the sum of its proper divisors (4257770275).

21288851345 is an equidigital number, since it uses as much as digits as its factorization.

21288851345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4257770274.

The product of its digits is 614400, while the sum is 47.

The spelling of 21288851345 in words is "twenty-one billion, two hundred eighty-eight million, eight hundred fifty-one thousand, three hundred forty-five".