21251574463249 has 27 divisors (see below), whose sum is σ = 23248779659217. Its totient is φ = 19417079916000.

The previous prime is 21251574463243. The next prime is 21251574463253. The reversal of 21251574463249 is 94236447515212.

The square root of 21251574463249 is 4609943.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 801571043025 + 20450003420224 = 895305^2 + 4522168^2 .

It is not a de Polignac number, because 21251574463249 - 2²¹ = 21251572366097 is a prime.

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 21251574463249.

It is not an unprimeable number, because it can be changed into a prime (21251574463243) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 6052853404 + ... + 6052856914.

Almost surely, 2^{21251574463249} is an apocalyptic number.

21251574463249 is the 4609943-rd square number.

21251574463249 is the 2304972-nd centered octagonal number.

It is an amenable number.

21251574463249 is a deficient number, since it is larger than the sum of its proper divisors (1997205195968).

21251574463249 is an frugal number, since it uses more digits than its factorization.

21251574463249 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7250 (or 3625 counting only the distinct ones).

The product of its digits is 14515200, while the sum is 55.

The spelling of 21251574463249 in words is "twenty-one trillion, two hundred fifty-one billion, five hundred seventy-four million, four hundred sixty-three thousand, two hundred forty-nine".