206417921 has 4 divisors (see below), whose sum is σ = 206450244. Its totient is φ = 206385600.

The previous prime is 206417909. The next prime is 206417941. The reversal of 206417921 is 129714602.

It is a happy number.

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 28569025 + 177848896 = 5345^2 + 13336^2 .

It is a cyclic number.

It is not a de Polignac number, because 206417921 - 2¹⁴ = 206401537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (206417941) 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, 3020 + ... + 20541.

It is an arithmetic number, because the mean of its divisors is an integer number (51612561).

Almost surely, 2^206417921 is an apocalyptic number.

It is an amenable number.

206417921 is a deficient number, since it is larger than the sum of its proper divisors (32323).

206417921 is an equidigital number, since it uses as much as digits as its factorization.

206417921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32322.

The product of its (nonzero) digits is 6048, while the sum is 32.

The square root of 206417921 is about 14367.2516856913. The cubic root of 206417921 is about 590.9931763799.

The spelling of 206417921 in words is "two hundred six million, four hundred seventeen thousand, nine hundred twenty-one".