204509781431 has 4 divisors (see below), whose sum is σ = 216539768592. Its totient is φ = 192479794272.

The previous prime is 204509781407. The next prime is 204509781439. The reversal of 204509781431 is 134187905402.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 204509781431 - 2¹⁸ = 204509519287 is a prime.

It is a super-2 number, since 2×204509781431² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (204509781439) 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, 6014993555 + ... + 6014993588.

It is an arithmetic number, because the mean of its divisors is an integer number (54134942148).

Almost surely, 2^204509781431 is an apocalyptic number.

204509781431 is a deficient number, since it is larger than the sum of its proper divisors (12029987161).

204509781431 is a wasteful number, since it uses less digits than its factorization.

204509781431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12029987160.

The product of its (nonzero) digits is 241920, while the sum is 44.

The spelling of 204509781431 in words is "two hundred four billion, five hundred nine million, seven hundred eighty-one thousand, four hundred thirty-one".