206661251 has 4 divisors (see below), whose sum is σ = 208707504. Its totient is φ = 204615000.

The previous prime is 206661241. The next prime is 206661253. The reversal of 206661251 is 152166602.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 206661251 - 2¹⁸ = 206399107 is a prime.

It is a super-3 number, since 3×206661251³ (a number of 26 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (206661253) 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, 1022975 + ... + 1023176.

It is an arithmetic number, because the mean of its divisors is an integer number (52176876).

Almost surely, 2^206661251 is an apocalyptic number.

206661251 is a deficient number, since it is larger than the sum of its proper divisors (2046253).

206661251 is a wasteful number, since it uses less digits than its factorization.

206661251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2046252.

The product of its (nonzero) digits is 4320, while the sum is 29.

The square root of 206661251 is about 14375.7174081852. The cubic root of 206661251 is about 591.2253104545.

The spelling of 206661251 in words is "two hundred six million, six hundred sixty-one thousand, two hundred fifty-one".