21278857873469 has 6 divisors (see below), whose sum is σ = 24752957118174. Its totient is φ = 18239021034360.

The previous prime is 21278857873397. The next prime is 21278857873477. The reversal of 21278857873469 is 96437875887212.

It can be written as a sum of positive squares in only one way, i.e., 13284836756569 + 7994021116900 = 3644837^2 + 2827370^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21278857873469 is a prime.

It is a super-2 number, since 2×21278857873469² (a number of 27 digits) contains 22 as substring.

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 21278857873469.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21278857873489) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 217131202742 + ... + 217131202839.

It is an arithmetic number, because the mean of its divisors is an integer number (4125492853029).

Almost surely, 2^{21278857873469} is an apocalyptic number.

It is an amenable number.

21278857873469 is a deficient number, since it is larger than the sum of its proper divisors (3474099244705).

21278857873469 is an equidigital number, since it uses as much as digits as its factorization.

21278857873469 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 434262405595 (or 434262405588 counting only the distinct ones).

The product of its digits is 2275983360, while the sum is 77.

The spelling of 21278857873469 in words is "twenty-one trillion, two hundred seventy-eight billion, eight hundred fifty-seven million, eight hundred seventy-three thousand, four hundred sixty-nine".