21206444061 has 16 divisors (see below), whose sum is σ = 32186856960. Its totient is φ = 12293590320.

The previous prime is 21206444059. The next prime is 21206444137. The reversal of 21206444061 is 16044460212.

It is a happy number.

It is not a de Polignac number, because 21206444061 - 2¹ = 21206444059 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21206444761) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13969231 + ... + 13970748.

It is an arithmetic number, because the mean of its divisors is an integer number (2011678560).

Almost surely, 2^21206444061 is an apocalyptic number.

It is an amenable number.

21206444061 is a deficient number, since it is larger than the sum of its proper divisors (10980412899).

21206444061 is a wasteful number, since it uses less digits than its factorization.

21206444061 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27940016.

The product of its (nonzero) digits is 9216, while the sum is 30.

The spelling of 21206444061 in words is "twenty-one billion, two hundred six million, four hundred forty-four thousand, sixty-one".