205404142021 has 24 divisors (see below), whose sum is σ = 232515387104. Its totient is φ = 180332792640.

The previous prime is 205404142007. The next prime is 205404142087. The reversal of 205404142021 is 120241404502.

It is a de Polignac number, because none of the positive numbers 2^k-205404142021 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205404142001) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 592306 + ... + 872716.

Almost surely, 2^205404142021 is an apocalyptic number.

It is an amenable number.

205404142021 is a deficient number, since it is larger than the sum of its proper divisors (27111245083).

205404142021 is a wasteful number, since it uses less digits than its factorization.

205404142021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 280549 (or 280520 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 25.

Adding to 205404142021 its reverse (120241404502), we get a palindrome (325645546523).

The spelling of 205404142021 in words is "two hundred five billion, four hundred four million, one hundred forty-two thousand, twenty-one".