21120042061 has 2 divisors, whose sum is σ = 21120042062. Its totient is φ = 21120042060.

The previous prime is 21120042023. The next prime is 21120042071. The reversal of 21120042061 is 16024002112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15864662025 + 5255380036 = 125955^2 + 72494^2 .

It is a cyclic number.

It is not a de Polignac number, because 21120042061 - 2⁷ = 21120041933 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21120042001) 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 as a sum of consecutive naturals, namely, 10560021030 + 10560021031.

It is an arithmetic number, because the mean of its divisors is an integer number (10560021031).

Almost surely, 2^21120042061 is an apocalyptic number.

It is an amenable number.

21120042061 is a deficient number, since it is larger than the sum of its proper divisors (1).

21120042061 is an equidigital number, since it uses as much as digits as its factorization.

21120042061 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 192, while the sum is 19.

Adding to 21120042061 its reverse (16024002112), we get a palindrome (37144044173).

The spelling of 21120042061 in words is "twenty-one billion, one hundred twenty million, forty-two thousand, sixty-one".