206642661 has 8 divisors (see below), whose sum is σ = 285024480. Its totient is φ = 133011312.

The previous prime is 206642593. The next prime is 206642677. The reversal of 206642661 is 166246602.

206642661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 206642661 - 2¹⁹ = 206118373 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (206642561) 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, 1187515 + ... + 1187688.

It is an arithmetic number, because the mean of its divisors is an integer number (35628060).

Almost surely, 2^206642661 is an apocalyptic number.

It is an amenable number.

206642661 is a deficient number, since it is larger than the sum of its proper divisors (78381819).

206642661 is a wasteful number, since it uses less digits than its factorization.

206642661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2375235.

The product of its (nonzero) digits is 20736, while the sum is 33.

The square root of 206642661 is about 14375.0708172169. The cubic root of 206642661 is about 591.2075822349.

The spelling of 206642661 in words is "two hundred six million, six hundred forty-two thousand, six hundred sixty-one".