205126421 has 4 divisors (see below), whose sum is σ = 208603200. Its totient is φ = 201649644.

The previous prime is 205126417. The next prime is 205126429. The reversal of 205126421 is 124621502.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 205126421 - 2² = 205126417 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205126429) 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, 1738301 + ... + 1738418.

It is an arithmetic number, because the mean of its divisors is an integer number (52150800).

Almost surely, 2^205126421 is an apocalyptic number.

It is an amenable number.

205126421 is a deficient number, since it is larger than the sum of its proper divisors (3476779).

205126421 is an equidigital number, since it uses as much as digits as its factorization.

205126421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3476778.

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 205126421 is about 14322.2351956669. The cubic root of 205126421 is about 589.7580363756.

Adding to 205126421 its reverse (124621502), we get a palindrome (329747923).

The spelling of 205126421 in words is "two hundred five million, one hundred twenty-six thousand, four hundred twenty-one".