21142444061 has 4 divisors (see below), whose sum is σ = 21146703900. Its totient is φ = 21138184224.

The previous prime is 21142443989. The next prime is 21142444109. The reversal of 21142444061 is 16044424112.

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 14807239225 + 6335204836 = 121685^2 + 79594^2 .

It is a cyclic number.

It is not a de Polignac number, because 21142444061 - 2³⁰ = 20068702237 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21142440061) 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, 2122466 + ... + 2132403.

It is an arithmetic number, because the mean of its divisors is an integer number (5286675975).

Almost surely, 2^21142444061 is an apocalyptic number.

It is an amenable number.

21142444061 is a deficient number, since it is larger than the sum of its proper divisors (4259839).

21142444061 is an equidigital number, since it uses as much as digits as its factorization.

21142444061 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4259838.

The product of its (nonzero) digits is 6144, while the sum is 29.

Adding to 21142444061 its reverse (16044424112), we get a palindrome (37186868173).

The spelling of 21142444061 in words is "twenty-one billion, one hundred forty-two million, four hundred forty-four thousand, sixty-one".