206061021661 has 32 divisors (see below), whose sum is σ = 233711493120. Its totient is φ = 179986017600.

The previous prime is 206061021589. The next prime is 206061021703. The reversal of 206061021661 is 166120160602.

It is a cyclic number.

It is not a de Polignac number, because 206061021661 - 2¹¹ = 206061019613 is a prime.

It is a super-2 number, since 2×206061021661² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (206061021161) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 104439471 + ... + 104441443.

It is an arithmetic number, because the mean of its divisors is an integer number (7303484160).

Almost surely, 2^206061021661 is an apocalyptic number.

It is an amenable number.

206061021661 is a deficient number, since it is larger than the sum of its proper divisors (27650471459).

206061021661 is a wasteful number, since it uses less digits than its factorization.

206061021661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4057.

The product of its (nonzero) digits is 5184, while the sum is 31.

The spelling of 206061021661 in words is "two hundred six billion, sixty-one million, twenty-one thousand, six hundred sixty-one".