206417628075221 has 4 divisors (see below), whose sum is σ = 208421682716832. Its totient is φ = 204413573433612.

The previous prime is 206417628075137. The next prime is 206417628075223. The reversal of 206417628075221 is 122570826714602.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-206417628075221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (206417628075223) 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, 1002027320651 + ... + 1002027320856.

It is an arithmetic number, because the mean of its divisors is an integer number (52105420679208).

Almost surely, 2^{206417628075221} is an apocalyptic number.

It is an amenable number.

206417628075221 is a deficient number, since it is larger than the sum of its proper divisors (2004054641611).

206417628075221 is a wasteful number, since it uses less digits than its factorization.

206417628075221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2004054641610.

The product of its (nonzero) digits is 4515840, while the sum is 53.

The spelling of 206417628075221 in words is "two hundred six trillion, four hundred seventeen billion, six hundred twenty-eight million, seventy-five thousand, two hundred twenty-one".