206643631 has 16 divisors (see below), whose sum is σ = 218004480. Its totient is φ = 195639840.

The previous prime is 206643623. The next prime is 206643637. The reversal of 206643631 is 136346602.

It is a cyclic number.

It is not a de Polignac number, because 206643631 - 2³ = 206643623 is a prime.

It is a super-2 number, since 2×206643631² = 85403180465728322, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 206643593 and 206643602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (206643637) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 575430 + ... + 575788.

It is an arithmetic number, because the mean of its divisors is an integer number (13625280).

Almost surely, 2^206643631 is an apocalyptic number.

206643631 is a deficient number, since it is larger than the sum of its proper divisors (11360849).

206643631 is a wasteful number, since it uses less digits than its factorization.

206643631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 774.

The product of its (nonzero) digits is 15552, while the sum is 31.

The square root of 206643631 is about 14375.1045561415. The cubic root of 206643631 is about 591.2085072947.

The spelling of 206643631 in words is "two hundred six million, six hundred forty-three thousand, six hundred thirty-one".