21485255669 has 4 divisors (see below), whose sum is σ = 21510444396. Its totient is φ = 21460066944.

The previous prime is 21485255647. The next prime is 21485255681. The reversal of 21485255669 is 96655258412.

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 7386543025 + 14098712644 = 85945^2 + 118738^2 .

It is a cyclic number.

It is not a de Polignac number, because 21485255669 - 2⁸ = 21485255413 is a prime.

It is a super-3 number, since 3×21485255669³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

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 21485255669.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21485255609) 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, 12593084 + ... + 12594789.

It is an arithmetic number, because the mean of its divisors is an integer number (5377611099).

Almost surely, 2^21485255669 is an apocalyptic number.

It is an amenable number.

21485255669 is a deficient number, since it is larger than the sum of its proper divisors (25188727).

21485255669 is an equidigital number, since it uses as much as digits as its factorization.

21485255669 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25188726.

The product of its digits is 5184000, while the sum is 53.

The spelling of 21485255669 in words is "twenty-one billion, four hundred eighty-five million, two hundred fifty-five thousand, six hundred sixty-nine".