205406421 has 8 divisors (see below), whose sum is σ = 298773024. Its totient is φ = 124488720.

The previous prime is 205406293. The next prime is 205406423. The reversal of 205406421 is 124604502.

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

It is not a de Polignac number, because 205406421 - 2⁷ = 205406293 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 205406391 and 205406400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205406423) 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 7 ways as a sum of consecutive naturals, for example, 3112186 + ... + 3112251.

It is an arithmetic number, because the mean of its divisors is an integer number (37346628).

Almost surely, 2^205406421 is an apocalyptic number.

It is an amenable number.

205406421 is a deficient number, since it is larger than the sum of its proper divisors (93366603).

205406421 is a wasteful number, since it uses less digits than its factorization.

205406421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6224451.

The product of its (nonzero) digits is 1920, while the sum is 24.

The square root of 205406421 is about 14332.0068727307. The cubic root of 205406421 is about 590.0262566118.

The spelling of 205406421 in words is "two hundred five million, four hundred six thousand, four hundred twenty-one".