21004120244 has 24 divisors (see below), whose sum is σ = 37337059200. Its totient is φ = 10336651776.

The previous prime is 21004120243. The next prime is 21004120271. The reversal of 21004120244 is 44202140012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21004120243) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 293957 + ... + 358355.

It is an arithmetic number, because the mean of its divisors is an integer number (1555710800).

Almost surely, 2^21004120244 is an apocalyptic number.

It is an amenable number.

21004120244 is a deficient number, since it is larger than the sum of its proper divisors (16332938956).

21004120244 is a wasteful number, since it uses less digits than its factorization.

21004120244 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65687 (or 65685 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 20.

Adding to 21004120244 its reverse (44202140012), we get a palindrome (65206260256).

The spelling of 21004120244 in words is "twenty-one billion, four million, one hundred twenty thousand, two hundred forty-four".