21084723241 has 4 divisors (see below), whose sum is σ = 21086331732. Its totient is φ = 21083114752.

The previous prime is 21084723239. The next prime is 21084723259. The reversal of 21084723241 is 14232748012.

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 11860081216 + 9224642025 = 108904^2 + 96045^2 .

It is a cyclic number.

It is not a de Polignac number, because 21084723241 - 2¹ = 21084723239 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21084723197 and 21084723206.

It is not an unprimeable number, because it can be changed into a prime (21084723221) 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, 784420 + ... + 810853.

It is an arithmetic number, because the mean of its divisors is an integer number (5271582933).

Almost surely, 2^21084723241 is an apocalyptic number.

It is an amenable number.

21084723241 is a deficient number, since it is larger than the sum of its proper divisors (1608491).

21084723241 is a wasteful number, since it uses less digits than its factorization.

21084723241 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1608490.

The product of its (nonzero) digits is 21504, while the sum is 34.

The spelling of 21084723241 in words is "twenty-one billion, eighty-four million, seven hundred twenty-three thousand, two hundred forty-one".