206718421 has 16 divisors (see below), whose sum is σ = 254781184. Its totient is φ = 163327104.

The previous prime is 206718397. The next prime is 206718439. The reversal of 206718421 is 124817602.

It is a cyclic number.

It is not a de Polignac number, because 206718421 - 2¹⁵ = 206685653 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (206718451) 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, 95665 + ... + 97801.

It is an arithmetic number, because the mean of its divisors is an integer number (15923824).

Almost surely, 2^206718421 is an apocalyptic number.

It is an amenable number.

206718421 is a deficient number, since it is larger than the sum of its proper divisors (48062763).

206718421 is a wasteful number, since it uses less digits than its factorization.

206718421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3220.

The product of its (nonzero) digits is 5376, while the sum is 31.

The square root of 206718421 is about 14377.7056931904. The cubic root of 206718421 is about 591.2798235518.

It can be divided in two parts, 20671 and 8421, that added together give a palindrome (29092).

The spelling of 206718421 in words is "two hundred six million, seven hundred eighteen thousand, four hundred twenty-one".