206511421 has 4 divisors (see below), whose sum is σ = 206723772. Its totient is φ = 206299072.

The previous prime is 206511377. The next prime is 206511433. The reversal of 206511421 is 124115602.

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

It can be written as a sum of positive squares in 2 ways, for example, as 143880025 + 62631396 = 11995^2 + 7914^2 .

It is a cyclic number.

It is not a de Polignac number, because 206511421 - 2¹⁵ = 206478653 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 206511392 and 206511401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (206514421) 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, 104710 + ... + 106663.

It is an arithmetic number, because the mean of its divisors is an integer number (51680943).

Almost surely, 2^206511421 is an apocalyptic number.

It is an amenable number.

206511421 is a deficient number, since it is larger than the sum of its proper divisors (212351).

206511421 is an equidigital number, since it uses as much as digits as its factorization.

206511421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 212350.

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 206511421 is about 14370.5052451193. The cubic root of 206511421 is about 591.0823958956.

The spelling of 206511421 in words is "two hundred six million, five hundred eleven thousand, four hundred twenty-one".