21249184441 has 3 divisors (see below), whose sum is σ = 21249330213. Its totient is φ = 21249038670.

The previous prime is 21249184433. The next prime is 21249184447. The reversal of 21249184441 is 14448194212.

The square root of 21249184441 is 145771.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 21249184441 - 2³ = 21249184433 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21249184394 and 21249184403.

It is not an unprimeable number, because it can be changed into a prime (21249184447) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 72886 + ... + 218656.

It is an arithmetic number, because the mean of its divisors is an integer number (7083110071).

Almost surely, 2^21249184441 is an apocalyptic number.

21249184441 is the 145771-st square number.

21249184441 is the 72886-th centered octagonal number.

It is an amenable number.

21249184441 is a deficient number, since it is larger than the sum of its proper divisors (145772).

21249184441 is an frugal number, since it uses more digits than its factorization.

21249184441 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 291542 (or 145771 counting only the distinct ones).

The product of its digits is 73728, while the sum is 40.

The spelling of 21249184441 in words is "twenty-one billion, two hundred forty-nine million, one hundred eighty-four thousand, four hundred forty-one".