21402040244 has 12 divisors (see below), whose sum is σ = 40334614404. Its totient is φ = 9877864704.

The previous prime is 21402040241. The next prime is 21402040271. The reversal of 21402040244 is 44204020412.

It can be written as a sum of positive squares in 2 ways, for example, as 1805400100 + 19596640144 = 42490^2 + 139988^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21402040241) 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, 205788797 + ... + 205788900.

It is an arithmetic number, because the mean of its divisors is an integer number (3361217867).

Almost surely, 2^21402040244 is an apocalyptic number.

It is an amenable number.

21402040244 is a deficient number, since it is larger than the sum of its proper divisors (18932574160).

21402040244 is a wasteful number, since it uses less digits than its factorization.

21402040244 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 411577714 (or 411577712 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 23.

Adding to 21402040244 its reverse (44204020412), we get a palindrome (65606060656).

The spelling of 21402040244 in words is "twenty-one billion, four hundred two million, forty thousand, two hundred forty-four".