205211421 has 8 divisors (see below), whose sum is σ = 304016960. Its totient is φ = 136807596.

The previous prime is 205211417. The next prime is 205211423. The reversal of 205211421 is 124112502.

205211421 is a `hidden beast` number, since 2 + 0 + 521 + 142 + 1 = 666.

It is not a de Polignac number, because 205211421 - 2² = 205211417 is a prime.

It is a super-2 number, since 2×205211421² = 84223454617678482, 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 = 205211394 and 205211403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205211423) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3800185 + ... + 3800238.

It is an arithmetic number, because the mean of its divisors is an integer number (38002120).

Almost surely, 2^205211421 is an apocalyptic number.

It is an amenable number.

205211421 is a deficient number, since it is larger than the sum of its proper divisors (98805539).

205211421 is an equidigital number, since it uses as much as digits as its factorization.

205211421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7600432 (or 7600426 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

The square root of 205211421 is about 14325.2023022364. The cubic root of 205211421 is about 589.8394861636.

Adding to 205211421 its reverse (124112502), we get a palindrome (329323923).

The spelling of 205211421 in words is "two hundred five million, two hundred eleven thousand, four hundred twenty-one".