205550013421 has 4 divisors (see below), whose sum is σ = 216368435200. Its totient is φ = 194731591644.

The previous prime is 205550013407. The next prime is 205550013439. The reversal of 205550013421 is 124310055502.

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 205550013421 - 2⁷ = 205550013293 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 205550013421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205550013451) 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, 5409210861 + ... + 5409210898.

It is an arithmetic number, because the mean of its divisors is an integer number (54092108800).

Almost surely, 2^205550013421 is an apocalyptic number.

It is an amenable number.

205550013421 is a deficient number, since it is larger than the sum of its proper divisors (10818421779).

205550013421 is a wasteful number, since it uses less digits than its factorization.

205550013421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10818421778.

The product of its (nonzero) digits is 6000, while the sum is 28.

Adding to 205550013421 its reverse (124310055502), we get a palindrome (329860068923).

The spelling of 205550013421 in words is "two hundred five billion, five hundred fifty million, thirteen thousand, four hundred twenty-one".