21042120044 has 12 divisors (see below), whose sum is σ = 40171320168. Its totient is φ = 9564600000.

The previous prime is 21042120041. The next prime is 21042120053. The reversal of 21042120044 is 44002124012.

It is a super-2 number, since 2×21042120044² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21042119998 and 21042120025.

It is not an unprimeable number, because it can be changed into a prime (21042120041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 239114957 + ... + 239115044.

It is an arithmetic number, because the mean of its divisors is an integer number (3347610014).

Almost surely, 2^21042120044 is an apocalyptic number.

It is an amenable number.

21042120044 is a deficient number, since it is larger than the sum of its proper divisors (19129200124).

21042120044 is a wasteful number, since it uses less digits than its factorization.

21042120044 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 478230016 (or 478230014 counting only the distinct ones).

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

Adding to 21042120044 its reverse (44002124012), we get a palindrome (65044244056).

The spelling of 21042120044 in words is "twenty-one billion, forty-two million, one hundred twenty thousand, forty-four".