206605146721 has 4 divisors (see below), whose sum is σ = 206606740672. Its totient is φ = 206603552772.

The previous prime is 206605146677. The next prime is 206605146731. The reversal of 206605146721 is 127641506602.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 127641506602 = 2 ⋅63820753301.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-206605146721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (206605146731) 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, 583485 + ... + 868138.

It is an arithmetic number, because the mean of its divisors is an integer number (51651685168).

Almost surely, 2^206605146721 is an apocalyptic number.

It is an amenable number.

206605146721 is a deficient number, since it is larger than the sum of its proper divisors (1593951).

206605146721 is a wasteful number, since it uses less digits than its factorization.

206605146721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1593950.

The product of its (nonzero) digits is 120960, while the sum is 40.

The spelling of 206605146721 in words is "two hundred six billion, six hundred five million, one hundred forty-six thousand, seven hundred twenty-one".