206155621 has 8 divisors (see below), whose sum is σ = 236003264. Its totient is φ = 176407200.

The previous prime is 206155613. The next prime is 206155657. The reversal of 206155621 is 126551602.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 206155621 - 2³ = 206155613 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 206155621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (206153621) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20295 + ... + 28708.

It is an arithmetic number, because the mean of its divisors is an integer number (29500408).

Almost surely, 2^206155621 is an apocalyptic number.

It is an amenable number.

206155621 is a deficient number, since it is larger than the sum of its proper divisors (29847643).

206155621 is an equidigital number, since it uses as much as digits as its factorization.

206155621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49611.

The product of its (nonzero) digits is 3600, while the sum is 28.

The square root of 206155621 is about 14358.1203853429. The cubic root of 206155621 is about 590.7427407310.

The spelling of 206155621 in words is "two hundred six million, one hundred fifty-five thousand, six hundred twenty-one".